This article explains an example on changing a signing key for ID tokens. In order to have Authlete to sign an ID token with the new key, you may have to configure both a service of Authlete and a client registered to the service.
Service settings
Register a JWK set document to "JWK Set Content" section in Service Settings. See the following article for instructions.
After the registration, add the value of "kid" of this keypair set ("1" in this example) to "ID Token Signature Key ID" section in the same "JWK Set" tab.
In order for the Authlete service to issue an ID token signed with the new key (signature algorithm: ES256), choose "ES256" on "ID Token Signature Algorithm" section in Client Settings.