SPR # DPOL6S8M65 - A method should be provided to upgrade an existing user to a roaming user using LotusScript.
There is currently no way to achieve such an upgrade through LotusScript. The NotesAdministrationProcess class provides a MoveRoamingUser method for moving a user's roaming files however this is only applicable to existing roaming users. The IsRoamingUser property of the NotesRegistration class can be used to specify that a user is a roaming user however this must be set before registering the user.
This does not appear to be possible through the C++ API either.