I have changed from FT to PT and back again over the years. IIRC you are limited at MModal to making a change like this once a year (maybe it was 6 months, lol, but there is a limit to how often you can do it!) unless there is some kind of hardship. Normally I have been able to work within the same basic time frame I was already in. Moving to FT it has been more dependent on where they need coverage. But this part of it may vary between pods and accounts.