It is possible to retrieve a list of all reservations made by a particular guest.
You can then view or edit those reservations (if the reservation is not cancelled).

You can either:
Click Guests -> Guests
​

or
Click Reservations -> Guests
​

Enter the guests name in the Search field.  As you type, matching guests will be listed. Select the desired guests Reservation History by clicking the 'View History' button.
​

When the 'View History' button is clicked, a list of reservations can be seen.
You can then click 'Edit' (if the reservation item isn't cancelled) or 'View' to see the reservation confirmation/cancellation in a new window.

If you click 'Edit' you will see the Reservation in the edit reservation view/page.

The list of the guests reservations will stay above the reservation you are editing. 

Once you are editing a reservation, you cannot edit another reservation by clicking 'Edit', until you close the current Reservation being edited.  The 'Edit' button will be faded and cannot be clicked until you close any Reservations being edited.