It sounds like you originally filed your return and answered "No" to anyone claiming you as their dependent? Now you need to amend so your Mom can claim you?
First you need to open up your original Turbo Tax file/account where your original return is located. Once you are in the return, go to the search box and type amend. You will get a jump-to option which will walk you through the amend process.
The screen you are looking for to change your dependent status( not claim your self) is in the personal information section of the return. I am going to attach a screen shot. Make sure you answer "Yes".
Amended tax returns must be printed and mailed into the IRS. See below for more information.
https://ttlc.intuit.com/replies/6602873
