You can do it like this:
Oracle:
UPDATE WTPart
SET branchIdA2typeDefinitionRefe = 126962,
Ida2typedefinitionreference = 126966
Where Branchida2typedefinitionrefe In (36374)
AND Ida3masterreference in (select ida2a2 from wtpartmaster where WTPartNumber in ('2000783'.'2000789'));
MS SQL:
UPDATE pdmlink.WTPart
SET branchIdA2typeDefinitionRefe = 61479,
idA2typeDefinitionReference = 492826
WHERE branchIdA2typeDefinitionRefe IN (71144)
AND idA3masterReference IN (select idA2A2 from pdmlink.WTPartMaster where WTPartNumber in ('2000783','2000789'));