Technically you can only have 1 account per ID with T212.
So one option is to request delete of current and request new with USD.
Or create 2nd account using ID of spouse or family member 
However you need to fund that accouny using resources from the member so that might not be most feasible approach.
We have idea on community to have multi currency in t212 , however no commitments to add feature of yet. See link below.