How to change a REST endpoint path in production

Instead of immediately changing the old one, which would break all your clients, do the following

1. Add the new path as a new endpoint which calls everything the old endpoint called, but with the new functionality. Separating the service code into a new class helps with this a lot, to minimize duplication of code. (Separation of Concerns)
2. Check the new endpoint into production.
3. Change the client to use the new endpoint.
4. As soon as no clients are using the old endpoint, you can safely remove it.