Usually the IRS mails back the entire tax return for the signature ... if one never sends the signed copy back the return is considered never filed ... this is the old fashioned way of rejecting the return before electronic media came in fashion. So you can efile the return at this time as the return is being "held" at the door and has not been allowed into the system yet ... it should go thru just fine however if it does gets rejected due to the "hold" you will have no choice but to mail the form back signed as required/requested.
