If the day of the sale has not been closed:
Go back to your sale, click on the 'Payment' button and select the new payment type.

If the day of the sale is already closed, it is not possible to change the payment method of the sale.
You need to make a reverse sale to cancel the sale (more information) and redo the sale.
The incorrect entry will be adjusted on the day of the reverse sale.
To avoid this issue, we recommend to use the store credit feature (more information) when you don’t know which payment method will be used to pay the sale.