The left and right cup racks are interchangeable and can be removed.
Slide the cup rack down into its closed position.

Locate the assembly slot a on the cup rack, align the slot with the bar, and firmly pop the rack off the support bar on that side.
The rack on the left pops free at the back. The rack on the right pops free at the front.

Slide the cup rack off the support bar on the opposite side.

Follow the instructions in reverse to replace the cup rack.