In Quickbooks, the display name is used as a unique identifier across Customer (also known as Donor, Tenants etc.), Employee and Vendor.
As such, trying to add another record with the same display name which already exists in any of the three types will give you an error: Another tenant, vendor or employee is already using this name. Please use a different name.
On Workato, you will receive a Duplicate Name Exists Error. Please see screenshot below:
One solution to this is to add a Prefix or Suffix before or after the Display name of the Customer, Employee or Vendor.
Do note however that QuickBooks does not allow for certain special characters in the Display Name including colon (:).