bp_set_user_member_type( int $user_id, string $member_type, bool $append = false )

function bp_set_user_member_type( $user_id, $member_type, $append = false ) {

	$retval = bp_set_object_terms( $user_id, $member_type, 'bp_member_type', $append );

	// Bust the cache if the type has been updated.
	if ( ! is_wp_error( $retval ) ) {
		wp_cache_delete( $user_id, 'bp_member_member_type' );

		/**
		 * Fires just after a user's profile type has been changed.
		 *
		 * @since BuddyPress (2.2.0)
		 *
		 * @param int    $user_id     ID of the user whose profile type has been updated.
		 * @param string $member_type profile type.
		 * @param bool   $append      Whether the type is being appended to existing types.
		 */
		do_action( 'bp_set_user_member_type', $user_id, $member_type, $append );
	}

	return $retval;
}