Looks like the NRA already told Dwaine to pound sand.
http://www.wfaa.com/news/local/dallas-county/dallas-mayor-pro-tem-dwaine-caraway-it-is-time-to-put-the-heat-on-the-nra/520525402
It takes years to pick a location and set one of these conventions into motion.
The idea that they could change on short notice is plain nuts.