When my customers order 1 youth small shirt and want to go back and order an adult large shirt, they can't.
Is there a way to get back to the order form without clearing out the cart out?
Sorry, FormsCentral currently does not support this.
There is a workaround, which the user can cancel at the PayPal transaction page, once the navigation is canceled, navigate to the web form URL again. Yes, you will have to start over again and it will not be a "continuing" shopping as in adding more items to the shopping cart list.
Hope this answers your question,