When there are multiple bookings under a single Guest Name, then any time you edit that Guest Data, you are effectively editing it for ALL the reservations that the guest is attached to.  This is a basic feature of a 'relational database' where a single Guest may be linked to multiple Bookings.

Sometimes this is what you want to do. However, sometimes you made multiple reservations and want to edit the individual Guest Data (such as the name and credit card 'Guarantee by' ) to become unique to each reservation.

In order to re-set existing bookings to the correct guest, please do the following:

• Search for the booking by Name or Confirmation #s (Ex. AD01450303)
• Under Booking Data, note the field at the bottom of the Guest Information section called: Guest ID. The number you see here is the 'database' ID' used to identify this Guest. You may wish to use this as a reference to see how many bookings this guest is attached to. You can find and search your Guest Database in the area called 'Guests' in the Setup | Relationships area.
• Click the 'Reset Guest ID' link next to the Guest ID and this releases the attachment the booking that had the guest's name. However, all the Guest's data is still there.
• Enter any new guests information and click Save. *Note the new Guest ID attached to the booking.

More details on this topic are available in the manual here.