My team is currently using the CMMI board in Team Services and we would like to switch to the Agile board. I was told we can't just change the template, but I can't figure out how to export all of our open tickets to a new board. How do I easily change our team's board. Thanks!
At the moment this is technically not possible. When you choose a Process, during project creation, you can't change it to a new parent later. So you pick CMMI, or Agile or Scrum and later you can only change to a derived template.
What you can do though, is create an inherited process template and customize it until it looks and feels the same as another process template. It's quite a bit of work, but doable.
It is expected that changing from one base template to another will be added somewhere in the future. But at the moment it's not showing up on the TFS/VSTS feature timeline.
There is no easy import/export option either, though there are a few tools, like VSTS Sync Migration Tool that can copy over work items and map them to a new structure. I'll probably just be as much work as creating an inhertited process though.