After you file

Yes ... due to the new laws put in place a couple of years ago you CANNOT amend a return to add a dependent whose SS# was issued after the original filing.  Sadly the TT program doesn't tell you this so you think you can and then the IRS says it is denied and sends a notice telling you so eventually.   What you can do is amend to take the OTHER dependent credit of up to $500  but you cannot get any other credits for this dependent.