Realizing that this is WAY after the fact, but I just ran into the same scenario for my daughters that share the same first initial. Nearly identical, I did one return, saved it, and then did the second return and erroneously saved it with the same name. Both returns had been submitted, so getting an 'e-file confirmation was going to be difficult.
Fortunately, I use Google Drive for nearly everything. So, I was able to locate the file within the web version of Google Drive, and through "manage versions" I was able to find the first file. I downloaded the file to my local hard drive, changed the file name to one of my daughters' full name, and put the file back up in my Google Drive with the rest of them. Upon restarting TT I found both files, intact. Once I opened them, the system was able to verify that they had been accepted.
I dodged a bullet there!!! I hope this helps someone else going forward.
