I noticed that, some users to which I have shared my form, are creating new entries (records) in the table; each time they visit the form; where in fact their aim is only to edit their previously entered own record. 

It is a simple "event registry" form, to which a person first says "No, I am not able to come" and, sometime later he wants to say that "Yes, I will come". The current version of the Zoho Form, is creating a new record for the next visit to the form; and thus I have two records now, for the same person. 

Is it possible to make the second entry an "updated entry" of the first one, thus changing or deleting the first record??

Thanks.