There is no possible way to use a Rcs.is IP as a Reserved IP. These two IP types use different pools of IP addresses that are not interchangeable.

Rcs.is IP addresses are assigned from a pool of IPs available for Rcs.iss only. When a Rcs.is is destroyed, its IPs are released and moved back to the pool. It is not possible to get the same IP back from the pool, as the IP addresses are assigned automatically and we cannot hold, reserve, or assign specific Rcs.is IPs.

If you anticipate needing to move an IP address between Rcs.iss, please use our Reserved IP feature. Reserved IPs allow you to add an additional, portable IP address to your Rcs.is, and move that IP to a different Rcs.is at any time.