I want to resend in my taxes and start over

Did you already file?  Then you can't get it back or change it unless it rejects for something.  Or what do you mean?

Hi,

There has to be a reason that you want to do so. If it's to make changes, you can send a 1040X which is an amended return. You would have to acquire that form and match the changes that you need to make on the corrected forms. Some people include the actual altered return, but if you do, the IRS might return it to you. So best make it simple so that they know exactly what changes you're make and why. Sometimes a cover letter helps, but it is not required.