Refresh Token upgrade to offline_token

My question is if it is possible to request an offline token using a refresh request and the normal refresh token using offline_access in the scope of the request?
I can get an offline token using the authorization request and continue to use it as an refresh token but I want to upgrade existing refresh tokens without having the users to log in again.

I have added the offline_access in the scope in my refresh request body but I continue to get a normal refresh token. Do I need to change offline_access to Default in my client configuration?

You can’t. This would also be against the spec, chapter 11 Offline Access: Final: OpenID Connect Core 1.0 incorporating errata set 2
The user MUST give consent to issuing an offline token.