Hi -
I'm new here, but I can answer your question. The cross bars can be removed by removing one of the end caps on each of the stationary bars. I have found the rear caps easiest to deal with. A word of caution, however, when removing the end caps....there is a small, yellow fastener that is under each end cap. These yellow fasteners (sort of look like small x-mas trees) are what hold the end cap on. In the process of pulling up the end cap you can VERY EASILY damage the yellow fastener as they are made of thin plastic and are really only good for a one-time use....installation at the factory. You will find that the components molded into the underneath of the end cap are also very weak in structure, and that by tugging on the cap to remove it, the plastic tabs can also easily break off. This will leave you unable to re-attach the end cap.
I can share this info. from a personal level as my '05 came without the crossbars. I ordered the crossbars from the dealership and experienced the problems that I spoke of above. Had to order a brand new endcap as one of them was beyond usage. Just be careful......