It can be problematic to change an address remotely. The best option is to do it in person from the directly attached console. To move the switch to a different subnet, that is indeed what is required. In your case, it's still in the same subnet with the same gateway, so you can just telnet in and change it. The instant the command is entered, your telnet session will stop, but you should be able to telnet to the new address and continue. (save the config, etc.)
When moving to a different subnet, the gateway has to be changed as well. You'll lose contact the instant either the gateway or address are changed. And the address has to change first. If you have machines in both networks, and changing the address of the switch will not otherwise break the network, then logging in to each network allows you a local path (not through a gateway) to the switch in either subnet. Change the address, go to the machine in the other network and continue your work.
If you have console (out-of-band) access, none of this mess is required.