Hey @Andrew Oswald ,
Thanks for reaching out! If the page is paid, you'll have to reach out to support via support.atlassian.com to get the page type changed.
If you're on a trial, you'll just need to go to the billing tab, and change page types in there. You can follow this guide when you're on a trial:
Let me know if you have any other questions,
- Abraham, Statuspage Support