change form fields after submission

Question

I want to see and change the inputs of my form after it was submitted i.e. at the .submit event listener.

$('.booking-form').submit( function(e){
    var em_booking_form = $(this);
    alert(em_booking_form);
}

It prints Object object but i couldn't find how to modify it/its fields. i also tried to flatten it but it just showed couple of Objects.

EDIT: later the form object goes to AJAX:

$.ajax({
...
data: em_booking_form.serializeArray(),
...

any ideas?