If you signed up before Aug 9, 2021, please click Previous plans to view your applicable plans.

This is because you already have a specific amount of full-time agents and only if one of them is made an occasional agent (who would log in using day passes) or if you delete the agent(tickets assigned to the agent would get unassigned) would you be able to decrease the full-time agent seat count under Admin > Account > Plans and Billings.