Replace or change a bill to a new or different customer:
If the name on the bill is the incorrect customer or guest, you can associate a different customer record with the bill. You can also create a new customer and associate it with the bill at the same time if the guest is not in your customer database.
[If the record shows the correct customer but has missing or incorrect information, see below for instructions on how to update the record from within the bill.]
To replace the customer: Click on the edit icon 
next to the name of the guest and then the "Change..." button. You can then type in the correct name of the guest. The system will search your database and attempt to find a match. If you find a match: Click on the corresponding record to associate this guest with the bill in place of the one previously set. Then click the "Assign to reservation" button on the bottom.
If you do not find a match: Click the "Create New Customer..." link, as seen below.
In the New Customer form, fill out the new customer's information to the best of your ability, then click the "Create and assign" button at the bottom of the form.
Update customer record from within the bill:
If the customer or guest's information on a bill needs to be updated, you can do so very quickly from within the reservation. For example, if you wanted to update the customer notes or update a phone number.
[You can also edit or update information on the customer record directly on the Customers page found in the black bar at the top.]
All bills and reservations associated with this customer will show the updated information once saved since the edit is being made for the customer, not the bill.
To update the customer: Click on the edit icon next to the name of the guest. 
A pop-up window will appear.
Update the guest's record and click the Update button on the bottom right. After you make changes here, the customer record you are editing will be updated, and changes will be reflected on all past and future bills and reservations.