I had the same issue with date, return was rejected.  I changed the date, e-filed and received error message of this return was already e-filed.  When I checked the EF Center view, the client's return type is "federal return" rather than "federal amended return".  Part VII box for file federal amended return electronically has an "X" in it.  What needs to be done to get it back to "federal amended return" so I can e-file the return?