The 10-Ticket Pass will never expire. Let us explain:
There is no time limit to book tickets with your 10-Ticket Pass. The pass will remain on your account indefinitely until you’ve used all 10 tickets.
Once you book a ticket with your 10-Ticket Pass, this ticket is treated the same as a single ticket. It has a specific location & time, and if you don't show up for the selected ride, you will lose this ticket.

You can always cancel or edit a ticket bought with a 10-Ticket Pass until the departure time. If you cancel a ticket, it will be credited back to your 10-Ticket Pass balance for future use.