Matt,
You can't actually switch a board from Kanban to Sprint. What you will need to do is create a new board (Sprint type) using the same Filter Query and probably the same columns definition etc.
You can then schedule when you will switch to Sprint mode and start using that board. And no Issues will be lost, they will just need to be assigned to the new Sprint.
Let me know if you need more.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.