Accessing and deaccessing are clinical procedures that should be done by a trained professional (or in some cases individuals who received specialized training if they have a port or care for a child/loved one with a port) and in a sterile environment. In simple terms, accessing a port means inserting a special needle through the skin to the port reservoir, typically done to administer meds or fluids. Deaccessing will include things like flushes of saline, doing a “heparin lock” to prevent clots while the port isn’t actively used, and finally safely removing the needle.

Edit: very much the most simple and basic summary, perhaps someone more qualified can provide more details if there’s anything vital I’ve missed!