I use jotform for registration details

If someone changes their email or mobile number is it possible for me to change their detail rather than them having to submit the entire form again

Sue

Yes it will be possible, all you need to do is to add an edit link into your form autoresponder(the confirmation email a submitter receives):

So in this way, the user will be able to edit just what she wants, and the information will be updated. If you have another question please open a new thread, we will be glad to assist you.