the show didn't sell out that fast. tickets were available for a few days, it's not like folks were shut out without having a chance to get any. a fast sell-out is minutes or seconds.
second, i suspect that the answer is "no" to moving the show. contracts have been signed & the venue has sold all the tickets - as far as they're concerned, this deal is in the bag and the only thing left is to collect money. so to move the show, the 930 would have to buy out the whole deal (including lost revenue from drink sales), and would probably need to include a lil' somethin' somethin' to entice the RnR to go through with this in the first place. i seriously doubt there is enough money available through increased ticket sales at the 930 to make this worthwhile.
in the end, the RnR have a popular, sold out show on their hands. why would they seek to give that up? booking popular bands is a competitive business, i don't see why they'd want to give away one of their biggest shows.
