Is it possible that the user who submitted the form can cancel his/her

The only option that I could think of is to include an EDIT LINK in the Autoresponder email (that your user receives) to provide an option to declare to cancel the request by editing the submission. This way, they can modify the contents from the information submitted by them. 

Please check out this guide to know more: How-to-Let-Users-Update-Their-Form-Submissions-at-a-Later-Date