That's what my recruiter said to do, but he also said that I risk having my entire offer be rescinded just for asking. Not sure if he's just trying to scare me away from doing that or not.I had to move my date (tentatively scheduled for November), but I just asked my recruiter about it. I wrote a justification and the recruiter sent it up the approval chain. I heard back with the approval just a few days after my request was put in. The whole process seemed pretty painless. YMMV but that was my experience.