An HOA (homeowners association) is the homeowners, acting as a corporate body. They can definitely change their fees.

However, those fees aren’t imposed just because someone felt like charging them. They pay for things, such as maintenance and community services. If the HOA wants to lower its fees, it has to budget accordingly. That might mean cutting back on luxury services (concierge, 24-hour security), renegotiating vendor agreements (gardening, maintenance), etc. I lived in one community that stopped heating its pool in the winter and cut back the hours for security patrols to control fees. But there’s only so much they can do. If the building is a 20-year old high rise with elevators, long-term maintenance issues, high insurance costs, etc., then the fees are still going to be high even if you fire the concierge, let the plants die, and stop washing the windows.