Only the updated 1099 information was changed. Once I entered that information, I saw that it was worth filing an amended return (I never had to do this before). But the original file was already autosaved before I exited that return and then used the "Amend a Return" option (I have already filed for both Federal and State). But the currently scheduled (original) payment amount minus the refund amount from the 1040X is a small enough amount that I'll just pay the extra few bucks and not waste unknown hours bouncing around the Treasury Dept. phone tree to cancel the current payment. Thanks to you both for the help!
