Steps to follow:
Step 1: Go to the Event dashboard > "Registration" tab > "Ticketing" tab
Step 2: Click on the edit icon for the ticket you wish to edit.
Step 3: If no tickets are sold for a tier yet, they can be updated (any fields) and saved.
Step 4: If at least one ticket is sold, then you can update the Quantity, Sale End date/time, and message attendees at any time. This can be used if you wish to extend or pause ticket sales.
Step 5: Click 'Save' to update changes.