While you can't directly convert a personal Facebook account to a Page, there are best practices and steps to follow to get your parish Facebook Page set up correctly.
- Create a new Facebook page for your parish following these steps.
- Alert your parishioners on the old "personal" profile that it is now a page with a new post. Link to the page and tell them to go like and follow it.
- Start posting to your new page.
- Invite all the friends on the personal account to like and follow the page by following this tutorial.
- After 90 days or so, delete the personal account and stick with your new page.