If you accidentally charged a tenant and pulled funds from their account and need to reimburse them you will to create a bill for the property to pay the tenant as the payee.
Create a bill
Select the property and owner
Select the tenant as the payee
Select your bill date and due date
The account will be an expense account such as Refunds
Select the unit
Your description should be easily understood by anyone who later sees the invoice such as Refund for error in collection for bill 2133
The amount would be the amount you are sending to the tenant
You can always add notes and attach a file
Post the bill
This bill is now in the payables tab where you can select it to process the payment for automatic transaction.