Hi @jsherman10,
I think you are talking about checkSession(). You can use check session to get a new token. The flow would go like this: send token to your custom API, the API returns a 401 expired token error, then you use checksession to silently renew the access token and make another call to the API.
P.S. a refresh token is a whole different type of token. You are talking about renewing an access token.