I see you posted a similar question to the Microsoft RMS (Cloud) forum, but I interpreted it differently. Don't do this (unless you're using HYOK with the Azure Information Protection client) - it's not supported for a good reason!
Some very unpredictable things can happen, especially with regard to templates when clients don't have a single authoritative source. If you've already activated Azure RMS and already created some custom templates, you can still migrate and have a reliable
outcome - but need to take some additional steps. It's covered in the migration documentation.