cabin air filter replace on 2003 GMC Sierra 2500 HD

can anyone tell me how to replace a cabin air filter?

Asked by for the 2003 GMC Sierra 2500 HD
This Article has been updated by bulletin #PIT3330, dated December 22, 2004.

A customer may inquire about the availability of the passenger compartment air filter.

Starting in 2003 model year, the passenger compartment air filter is no longer available as a factory option. With the redesigned HVAC case, there is no longer a cavity for the filter. The GM parts catalog indicates there is a replacement filter available; however, there is no provision for it.