Find the commitment you are protecting
An owner, volunteer, or community member can be asked to make many worthwhile commitments. Before composing the refusal, name what you can actually give: time, attention, money, access, or responsibility. A limit becomes easier to express when it describes your capacity rather than the worth of the request.
Answer the request that was made
A concise answer might be: "I cannot take responsibility for the event this season." A long account of every competing obligation can invite the recipient to solve those obligations for you. You can offer context if you want, but you do not need to present a case that earns permission to decline.
Offer an alternative only when it is real
"I can review one page on Friday" is a bounded alternative. "Happy to help however I can" reopens the commitment you just declined. Do not offer another person's time or contact details without permission. Sometimes the accurate answer ends after the no.
Leave room for disappointment
The recipient may be disappointed. That does not automatically make your wording unkind or your limit wrong. You can acknowledge the impact without reversing a decision you cannot sustain: "I know this leaves a gap. I am not able to own it." Avoid adding blame or a lesson about how the other person should have planned.
Check obligations before treating it as optional
A social invitation differs from a contract, professional duty, employment responsibility, or safety matter. Check the obligations and use the proper process where they apply. This exercise concerns wording; it does not decide whether you are legally or professionally free to decline.
Keep the boundary in the follow-through
If you agreed to review one page, do that rather than silently becoming responsible for the whole project. If the request expands, name the change and decide again. A boundary that survives ordinary use is more helpful than a perfectly phrased sentence that you cannot keep.