change title and text for one form

Hi

I need to change the text for one form.
for other forms, the default text should remain.

I try this but in is not working

document.addEventListener( 'wpcf7mailsent', function( event ) {
        if (event.detail.contactFormId == '257') {
            swal({
                title: '<strong>'+subscribe_information.title+'</strong>',
                type: 'success',
                html: subscribe_information.content,
                showCloseButton: true,
                showConfirmButton: false,
            });
        }
 }, false );