post https://live.getsilverfin.com/f//oauth/token/
Refresh Token
With the refresh token, you can request a new access token / refresh token pair:
Perform a POST request to /oauth/token with parameters: client_id, client_secret, refresh_token, redirect_uri and grant_type=refresh_token.
Each refresh token can be used only once. As soon as the new access token is used to access the API for the first time, the previous refresh token will be revoked.