CAL Ownership transfer

I've read the other similar questions, and the answers don't seem to help.

I am the owner of a trial Instance of SAP IDES on AWS. I want to allow another user to administer this instance, and ultimately take over ownership.

I've shared the tenant link to them, they have requested access, and I have granted admin/access.

While they can log in, the cannot see the instance in their list.

I then edited the Account, added them as a owner to the account assigned to the instance, and still no joy.

Is this because the instance is a trial? If so, the trial still has two weeks remaining, and it will be the new user's task to make it permanent.