Let's set up a new supplier to update your list and change the entity of your customer to supplier, kwanruen. 

Before we begin, I'd like to verify which specific area in your Chart of accounts you'd like to amend? Please don't hesitate to provide further details in the comments section so I can provide a precise solution.

QuickBooks Online (QBO) restrict duplicate names, so you'll need to create a new supplier profile to convert a customer into a supplier. Follow these steps to complete the process:

1. Set up a new supplier name.
   1. Go to Expenses and select Suppliers.
   2. Select New Supplier at the top right
   3. In the Supplier display name or Full name field, choose a name one keystroke different from the customer name (such as John J. Doe if the customer name was John Doe, for example).
   4. Enter the rest of the contact information.
   5. Select Save.
2. Run a Transaction List by Customer report to get the accounts, dates and amounts attached to the customer.
3. Manually transfer the transactions of your customer under the new supplier name.
4. Once all transactions are added, make the customer inactive (Delete a customer section).
5. Edit the Vendor name, if needed.

Moreover, would you like to pull up and customise reports to show all customer and vendor transactions? You can check out this article to guide you how: Print a customer or supplier register in QuickBooks Online.

You can always let me know in the comments if you have any other concerns about keeping your customers and supplier list organized. We in the Community will get you covered.