Can you have a customer as a vendor and a vendor as a customer?

Good afternoon, @debbie87. 

Thanks for bringing your question to the Community. I'm here to provide information with having a customer as a vendor in QuickBooks Online. 

You can add a vendor as a customer manually. Slightly changing the name of the Vendor or Customer to get around the duplicate name restriction is an option. For example, adding a period at the end of the name, and then creating the other one without one. 

Here are the steps on how to create a Customer: 

1. Hover over the Sales tab and pick Customers. 
2. Click on New Customer on the right-hand side. 
3. Enter the info needed to create the customer. 
4. Press Save when done. 

Here are several articles, including transactions between the two parties and managing lists: 

• How to record a Barter Transaction
• Manage your customer list

At this time, the feature to automatically change a Vendor to a Customer and a Customer to a Vendor isn't available. 

If you have any more questions or concerns, please don't hesitate to comment below. I'm always here to help. Have a good one!