Change Cancel Page URL For Paypal

add_filter( 'charitable_paypal_redirect_args', 'test_charitable_paypal_redirect_args', 10, 3 );

function test_charitable_paypal_redirect_args( $paypal_args, $donation_id, $processor ) {

	// locate the 'cancel_return' parameter and update it to a proper url

	$paypal_args['cancel_return'] = 'http://example.com/cancel';

	return $paypal_args;

}