A common method of credentialing for an API is to give each use a public/private key pair. The public key is sent in with the request, and the private key is used to sign the request (and is verified by the server re-signing the request and checking that they match).
The user can rotate the keys pretty easily. What I don't understand is why a key rotation involves changing the public key as well (this is done by AWS when an IAM user's key is rotated).
From my understanding the public key is kind of like a persons name, it tells the server who you are. It was never a secret to begin with. What benefit is gained by changing the public key and not just changing the private key?
Edit: Just to clarify, I am not referring to an RSA type encryption key pair which rely on each other. I am referring to key pairs used for API access (such as AWS uses)