Sequence Reset - Gap Fill messages (GapFillFlag=‘Y’) must be received in sequence. Any messages (including any Gap Fills) sent in response to a Resend Request should have PossDup=‘Y’.
Sequence Reset - Reset (GapFillFlag not ‘Y’) is used only as a last resort, and always by human intervention, to allow an otherwise hopelessly confused session to be resumed. In these cases all chance at automatic message recovery are lost.