When a person gets in touch with you for a consultation because he/she has an urgent problem, schedule an appointment at your earliest convenience. If the person does not respond, does not show up, or postpones the appointment, CANCEL EVERYTHING, because what it means is that his/her problem is not urgent at all.
Never drop everything for such persons. They are most often nosy creatures who seek to be entertained. If you have to schedule anything with them, do it at your convenience only. Let THEM drop everything for YOU.