Hi joelmhalbert,
Welcome to Community! QuickBooks Online enables you to edit accounts, so your Chart of accounts remains organized. I would be happy to assist!
Here's how to change an existing account into a subaccount;
1. Go to your Settings , and select Chart of accounts
2. Locate the account you want to edit
3. In the Action column, select Edit from the dropdown menu▼
4. Check Make this a subaccount, then select the Parent account you want it to be under
5. Hit Save.
You're all set!
If you have any other questions, feel free to reach out again. We would be glad to help!