We don’t believe in the “pending” status. Everyone we’ve talked to about it says they intend to use it, but don’t. With UserVoice Helpdesk we’ve simplified things: there are only “open” or “closed” tickets.
If you’re one of the few who actually use pending, you could replicate it by creating a custom field (Click on "Settings" in the Admin Header → Choose "Tickets" from the drop down menu → Scroll down to "Custom Fields.") that has “pending” and whatever other statuses you want.