At this point, you don't and you can't. The IRS will not start processing returns until Jan 28th. So you have to wait until then to see if it's accepted or rejected.
If the return is rejected, then just make your changes (DO *NOT* AMEND) and simply click the big orange TRANSMIT MY RETURNS NOW button again.
If the return is accepted, then you have to wait until the IRS processes your return completely and you have physical possession/control of your refund. Then you can file your amended return.
