Snippet to switch UPS account and origin address based on the destination. Supports WooCommerce UPS Shipping Plugin: https://www.pluginhive.com/product/woocommerce-ups-shipping-plugin-with-print-label/

functions.php

<?php

/**
*	Snippet to Change UPS account based on destination country while confirming shipment (not while generating packages).
*	
*/
add_filter( 'wf_ups_shipment_confirm_request_data', 'switch_origin_adress_based_on_country', 10, 2 );

if( ! function_exists('switch_origin_adress_based_on_country') )
{
		function switch_origin_adress_based_on_country( $request, $order ) {

				$ship_from_address = array(
						'US'		=>	array(													// US address
										'Name'				=> 'Varun',
										'AttentionName'		=> 'Varun',
										'PhoneNumber'		=> '1234567890',
										'EMailAddress'		=> '[email protected]',
										'ShipperNumber'		=> '589Y4Y',						//UPS account Number
										'Address'			=> array(
												'AddressLine1'		=> '128th main',
												'City'				=> 'california',
												'StateProvinceCode'	=> 'CA',
												'CountryCode'		=> 'US',
												'PostalCode'		=> '90001',
										),
										'units'				=> 'imperial',						//imperial for LBS /IN and metric for KG / CM
						),

						'EU'		=>	array(													// Europe address
										'Name'				=> 'Varun2',
										'AttentionName'		=> 'Varun2',
										'PhoneNumber'		=> '0123456789',
										'EMailAddress'		=> '[email protected]',
										'ShipperNumber'		=> '589Y4Y',						//UPS account Number
										'Address'			=> array(
												'AddressLine1'		=> '128th main',
												'City'				=> 'california',
												'StateProvinceCode'	=> 'CA',
												'CountryCode'		=> 'FR',
												'PostalCode'		=> '90001',
										),
										'units'				=> 'metric',
						)

				);

				if( ! empty($ship_from_address['EU']) && in_array( strtoupper($request['Shipment']['ShipTo']['Address']['CountryCode']), WC()->countries->get_european_union_countries() ) ) {
						$units = $shipper_address['units'];
						unset( $shipper_address['units'] );

					$request['Shipment']['Shipper'] = $ship_from_address['EU'];
				}
				elseif( ! empty($ship_from_address['US']) ) {
					$request['Shipment']['Shipper'] = $ship_from_address['US'];
				}

				foreach( $request['Shipment']['package'] as $key => $package ) {

					if( isset($package['Package']) ) {
						if( $units == 'metric' && strtoupper($request['Shipment']['package'][$key]['Package']['PackageWeight']['UnitOfMeasurement']['Code']) != 'KGS' ) {
							$request['Shipment']['package'][$key]['Package']['Dimensions']['UnitOfMeasurement']['Code'] 	= 'CM';
							$request['Shipment']['package'][$key]['Package']['Dimensions']['Length']	  = number_format( wc_get_dimension( $request['Shipment']['package'][$key]['Package']['Dimensions']['Length'], 'CM' ), 2, '.', '');

							$request['Shipment']['package'][$key]['Package']['Dimensions']['Width']		  = number_format( wc_get_dimension( $request['Shipment']['package'][$key]['Package']['Dimensions']['Width'], 'CM' ), 2, '.', '');

							$request['Shipment']['package'][$key]['Package']['Dimensions']['Height']	  = number_format( wc_get_dimension( $request['Shipment']['package'][$key]['Package']['Dimensions']['Height'], 'CM' ), 2, '.', '');

							$request['Shipment']['package'][$key]['Package']['PackageWeight']['UnitOfMeasurement']['Code'] 	= 'KGS';
							$request['Shipment']['package'][$key]['Package']['PackageWeight']['Weight']	     = number_format( wc_get_weight( $request['Shipment']['package'][$key]['Package']['PackageWeight']['Weight'], 'KGS' ), 2, '.', '');
						}
						elseif(  $units == 'imperial' && strtoupper($request['Shipment']['package'][$key]['Package']['PackageWeight']['UnitOfMeasurement']['Code']) != 'LBS' ) {
							$request['Shipment']['package'][$key]['Package']['Dimensions']['UnitOfMeasurement']['Code'] 	= 'IN';
							$request['Shipment']['package'][$key]['Package']['Dimensions']['Length']	  = number_format( wc_get_dimension( $request['Shipment']['package'][$key]['Package']['Dimensions']['Length'], 'IN' ), 2, '.', '');

							$request['Shipment']['package'][$key]['Package']['Dimensions']['Width']		  = number_format( wc_get_dimension( $request['Shipment']['package'][$key]['Package']['Dimensions']['Width'], 'IN' ), 2, '.', '');

							$request['Shipment']['package'][$key]['Package']['Dimensions']['Height']	  = number_format( wc_get_dimension( $request['Shipment']['package'][$key]['Package']['Dimensions']['Height'], 'IN' ), 2, '.', '');

							$request['Shipment']['package'][$key]['Package']['PackageWeight']['UnitOfMeasurement']['Code'] 	= 'LBS';
							$request['Shipment']['package'][$key]['Package']['PackageWeight']['Weight']	     = number_format( wc_get_weight( $request['Shipment']['package'][$key]['Package']['PackageWeight']['Weight'], 'LBS' ), 2, '.', '');
						}
					}
				}
				return $request;
		}
}


/**
*	Snippet to Change UPS account based on destination country on cart and checkout page.
*/
add_filter( 'wf_ups_shipment_settings', 'wf_ups_change_origin_address_and_unit');

if( ! function_exists('wf_ups_change_origin_address_and_unit') ) {
	function wf_ups_change_origin_address_and_unit( $settings ) {
		$alternate_accounts  =   array(
	        'US'    =>  array(         // shipping class to use alternative account
	            //Alternative account details.
	            'shipper_number'    =>  'XXXXXXXXXX',   		// UPS account number
	            'user_id'           =>  'XXXXXXXXXX',   		// UPS user ID
	            'password'          =>  'XXXXXXXXXX',   		// UPS password
	            'access_key'        =>  'XXXXXXXXXX',   		// UPS access key
	            'origin_addressline'=>  '420 9th Ave',  		// Origin address
	            'origin_postcode'   =>  '10001',        		// Origin postcode
	            'origin_city'       =>  'New York',     		// Origin City
	            'origin_state'      =>  'NY',           		// Origin State
	            'origin_country'    =>  'US',           		// Origin Country
	            'units'				=>	'imperial'				// imperial for LBS / IN and metric for KGS / CM
	        ),
	        'EU'    =>  array(         		
	            'shipper_number'    =>  '1111',   				// UPS account number
	            'user_id'           =>  '111',   				// UPS user ID
	            'password'          =>  '111111',   			// UPS password
	            'access_key'        =>  '111111111',   			// UPS access key
	            'origin_addressline'=>  '200 exp Ave',  		// Origin address
	            'origin_postcode'   =>  '30303',        		// Origin postcode
	            'origin_city'       =>  'Atlanta',     			// Origin City
	            'origin_state'      =>  'BH',           		// Origin State
	            'origin_country'    =>  'FR',           		// Origin Country
	            'units'				=>	'metric'				// imperial for LBS / IN and metric for KGS / CM
	        )
    	);

		if( is_cart() || is_checkout() ) {
			
			if( in_array( strtoupper(WC()->customer->get_shipping_country()), WC()->countries->get_european_union_countries() ) ) {

					if( ! empty($alternate_accounts['EU']['shipper_number']) )		$settings['shipper_number']     =   $alternate_accounts['EU']['shipper_number'];
				    if( ! empty($alternate_accounts['EU']['user_id']) )				$settings['user_id']            =   $alternate_accounts['EU']['user_id'];
				    if( ! empty($alternate_accounts['EU']['password']) )			$settings['password']           =   $alternate_accounts['EU']['password'];
				    if( ! empty($alternate_accounts['EU']['access_key']) )			$settings['access_key']         =   $alternate_accounts['EU']['access_key'];
				    if( ! empty($alternate_accounts['EU']['origin_addressline']) )	$settings['origin_addressline'] =   $alternate_accounts['EU']['origin_addressline'];
				    if( ! empty($alternate_accounts['EU']['origin_postcode']) )		$settings['origin_postcode']    =   $alternate_accounts['EU']['origin_postcode'];
				    if( ! empty($alternate_accounts['EU']['origin_city']) )			$settings['origin_city']        =   $alternate_accounts['EU']['origin_city'];
				    if( ! empty($alternate_accounts['EU']['origin_state']) )		$settings['origin_state']       =   $alternate_accounts['EU']['origin_state'];
				    if( ! empty($alternate_accounts['EU']['origin_country']) )		$settings['origin_country']     =   $alternate_accounts['EU']['origin_country'];
				    if( ! empty($alternate_accounts['EU']['units']) )				$settings['units']				=	$alternate_accounts['EU']['units'];
			}
			elseif( strtoupper(WC()->customer->get_shipping_country()) == 'US' ) {
					if( ! empty($alternate_accounts['US']['shipper_number']) )		$settings['shipper_number']     =   $alternate_accounts['US']['shipper_number'];
				    if( ! empty($alternate_accounts['US']['user_id']) )				$settings['user_id']            =   $alternate_accounts['US']['user_id'];
				    if( ! empty($alternate_accounts['US']['password']) )			$settings['password']           =   $alternate_accounts['US']['password'];
				    if( ! empty($alternate_accounts['US']['access_key']) )			$settings['access_key']         =   $alternate_accounts['US']['access_key'];
				    if( ! empty($alternate_accounts['US']['origin_addressline']) )	$settings['origin_addressline'] =   $alternate_accounts['US']['origin_addressline'];
				    if( ! empty($alternate_accounts['US']['origin_postcode']) )		$settings['origin_postcode']    =   $alternate_accounts['US']['origin_postcode'];
				    if( ! empty($alternate_accounts['US']['origin_city']) )			$settings['origin_city']        =   $alternate_accounts['US']['origin_city'];
				    if( ! empty($alternate_accounts['US']['origin_state']) )		$settings['origin_state']       =   $alternate_accounts['US']['origin_state'];
				    if( ! empty($alternate_accounts['US']['origin_country']) )		$settings['origin_country']     =   $alternate_accounts['US']['origin_country'];
				    if( ! empty($alternate_accounts['US']['units']) )				$settings['units']				=	$alternate_accounts['US']['units'];
			}
		}

		return $settings;
	}
}