There are two ways to use UR points. You checked via the UR Travel Portal and if they don't show the flight you're looking for you should check what is commercially available and then call Chase Travel Portal Customer Service to see if that can be booked.

The second way is transferring the points to airline programs for use in redeeming an award ticket. That is constrained by availability within the individual programs. UR has specific transfer partners that allow redemption at specific number of points & based on if award space is available when you want to travel.

Read up under the Chase forum below the airline programs on the Miles & Points menu. Lots of info there.