How do I get back into my return? I said I would mail the return, but I have NOT mailed it yet. I need to go back into the system to make further changes before I file.

TT kept telling me to mark an answer blank re 1099 filing, which I had done and also tried to make clear on the form, but TT system kept saying it was wrong so I could no efile. I said I would mail it and did not expect that TT would automatically close the return at that time and does not let me go in to make other changes that I still need to do. How do I get back into my return within TT?