Sometimes a client will create a new online profile with new details. This can create an extra profile for you in salon. To keep all the details in one place, follow these steps
Go to the new duplicate client profile -> Online Booking -> Make a note/copy the email they have a connected user with
Go to the original client profile -> Online Booking -> Connect -> Enter or paste the online booking user
Update any bookings which need to be on the original user
Go back to the duplicate account -> Edit -> Anonymise