It should be pretty easy due to the fact that it's by the spare tire. Here's from the manual. You could just buy a manual antenna if you don't want the automatic.
1. Remove cover and spare tire.
2. Remove radio antenna nut and radio antenna stanchion from electric antenna. (1 and 2)
3. Remove one nut and one bolt retaining electric antenna inside luggage compartment. (3 and 4)
4. Disconnect wire harness connector and radio antenna lead in cable from electric antenna and remove electric antenna from vehicle.