Change the word "Seat(s)" to "student(s)" for Paid Memberships Pro Sponsored Members Add On.

my-pmpro-change-seat-to-student.php

<?php   // do not copy this line.
/**
  * This will change all instances of seat(s) to student(s) for the Sponsored Members Add On 
  * https://www.paidmembershipspro.com/add-ons/pmpro-sponsored-members/
 * 
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
 
 function my_pmpro_change_seat_to_student( $output_text, $input_text, $domain ) {
	if ( 'pmpro-sponsored-members' === $domain ) {
		$output_text = str_replace( 'seats', 'students', $output_text );
		$output_text = str_replace( 'Seats', 'Students', $output_text );
		$output_text = str_replace( 'seat', 'student', $output_text );
	}
	return $output_text;
}
add_filter( 'gettext', 'my_pmpro_change_seat_to_student', 10, 3 );