DECLARE lastgood integer;
DECLARE firstbad integer;
DECLARE offset integer;

lastgood = ;
firstbad = ;
offset = firstbad - lastgood + 1;

Update MWTRN
Set [Entry Number] = [Entry Number] - offset
where [entry number] > lastgood;

Update MWPAX
Set [Charge Reference] = [Charge Reference] - offset
where [Charge Reference] > lastgood;

Update MWPAX
Set [Payment Reference] = [Payment Reference] - offset
where [Payment Reference] > lastgood;