I can walk you through the steps on how to make your customer inactive in QuickBooks Online (QBO).
Making your customer inactive doesn’t delete their transaction history. It just removed their name from the list of customers when creating a transaction. To get started, here’s how to make them inactive:
Go to the Sales menu.
Select the Customers tab.
Locate and click the customer’s name.
From your customer transaction page, click the Edit button.
Select Make inactive from the Customer information window.
Then select Yes when prompted.
Go back to the Customers tab and click the Gear icon.
Put a check-mark inside the Include inactive box. That way you can still view the name of your deleted customer from the Customers tab.
In regards to deleting your recurring invoice, you'll want to edit it and assign it to your new tenant. You can refer to the Edit an existing recurring template section of this article for the detailed steps: Create recurring transactions in QuickBooks Online.
Let me also share this link that can guide you in managing your customer list effectively. This resource provides complete information on how to add a sub-customer and merge them.
In case you have other follow-up questions with regards to handling your customer list, you can always post a reply in this thread. I’m just a post away from you. Keep safe and stay well.