Some time ago there was controversy that some active duty enlistments were lengthened and some were called back to active duty during a period of the Iraq war.
I don’t believe that stop was used in Viet Nam (we had the draft after all), and in WWII one served for the duration.
What about in the Korean War? I know that many vets of WWII in the inactive, individual reserve were called up, but were enlistments lengthened and did draftees have their service term lengthened?