Try using weighted recordsets.
set the weight of one to 0 and the other to 100, this will swap DNS records entirely. If the requirement is transition deployment slowly, then set the weights to give proportional responses (so, for example 400 and 400 will direct traffic equally).
Remember that DNS records are cached, so any changes might not take effect immediately. If you expect to do this a lot, set the TTL (time to live) to 60 seconds.