Cloudformation - Update CIDR Range in Stack WITHOUT Terminating All RDS, ELB's Instances

My client is try to increase the number of IP's available on a particular subnet for changing their CIDR range. The environment provisioning involved is driven by CloudFormation almost entirely. Is there a way to gracefully change the CIDR range without having to rebuild the entire CloudFormation stack? Otherwise, the client will need to migrate data off of the RDS databases at least into the new stack with the expanded CIDR range.

Thanks