You may decline, as others have suggested, but it's not always easy/desirable with family, or you could accept, but providing rules and boundaries. For example, you may look at your appointment calendar and find a free spot in a moment far enough in the future so to not block major clients ("ok, the earliest I can book a session for you is 18 march 2024 at 8.30 am"). If they protest, calmly explain that you are fully booked before and you have a lot of post production work to do too. If they insist on having it done before that date, offer to pay for them a session with another photographer (less expensive than you). Hopefully they'll understand that your time has a value.
You may decline, as others have suggested, but it's not always easy/desirable with family, or you could accept, but providing rules and boundaries. For example, you may look at your appointment calendar and find a free spot in a moment far enough in the future so to not block major clients ("ok, the earliest I can book a session for you is 18 march 2024 at 8.30 am"). If they protest, calmly explain that you are fully booked before and you have a lot of post production work to do too. If they insist on having it done before that date, offer to pay for them a session with another photographer (less expensive than you). Hopefully they'll understand that your time has a value.