Change my and friends profile data example: change user display name

functions.php

<?php
/**
 * Update my profile data before get BUC chat
 *
 * @param array $profile Get my profile data.
 * @return array
 */
function buc_update_my_profile_data( $profile ) {
	$user_info  = get_userdata( $profile['id'] );
	$first_name = $user_info->first_name;
	$last_name  = $user_info->last_name;
	if ( $first_name ) {
		$profile['fullname'] = $first_name . ' ' . $last_name;
	}
	return $profile;
}
add_filter( 'buc_before_get_my_profile', 'buc_update_my_profile_data', 10, 1 );

/**
 * Update friends profile data before get BUC chat
 *
 * @param array $profile Get friends profile data.
 * @return array
 */
function buc_update_friend_profile_data( $profile ) {
	$user_info  = get_userdata( $profile['id'] );
	$first_name = $user_info->first_name;
	$last_name  = $user_info->last_name;
	if ( $first_name ) {
		$profile['fullname'] = $first_name . ' ' . $last_name;
	}
	return $profile;
}
add_filter( 'buc_before_get_friends_profile', 'buc_update_friend_profile_data', 10, 1 );