GL Type

It's not possible to change the General Ledger type in QuickBooks Desktop (QBDT),  Deadwood AI. Let me share information with you. The best way is to create another account with the correct GL type. Then transfer the balance using a Journal Entry. 

For details check out this article to know when you can create a journal entry. 

And would I suggest working with your accountant for proper guidance on selecting the affected accounts when creating a GL type.

I'll leave this handy resource here that contains a detailed guide to personalizing reports in QBDT: 

• Customize reports in QuickBooks Desktop.
• Filter, sort, or total reports by Class.

You can consistently depend on the Community space for extra help with managing the General Ledger type, Deadwood AI. I'll be here to assist you whenever you require support.

RE: Is there any way to change the GL Type when an existing account was identified as the wrong type when set up?

Yes, but it depends on what the current account type is. For some, like A/R and A/P, you can't change the type. For others, it's allowed. It's also disallowed for "special" accounts, like Undeposited Funds and Sales Tax Payable.

For example, you can change a bank account type into many other types. Similarly, you can change income and expense accounts to be other types.

To change the type, edit the account from the chart of accounts and pick a different account type.  If it's not allowed, the field will either be disabled or you'll get a message saying the account is a special account and you can't change the type.