In addition to James L's points, I would add: First, use a good subject line, so that the advisor knows what your email is about, just from the subject line. For example, "Regrets, please cancel March 14th appointment." Be sure to include the word "cancel" and the date of the appointment. Second, given that you are cancelling the appointment, the basic courtesy is to make this clear as soon as possible, so that he can use that time slot. Therefore, you should also try to contact whoever in his office schedules appointments. This also has the advantage that the office person will probably just cancel the appointment, without discussion and without trying to talk you into making the appointment anyway. Third, I would avoid giving any reason. If you mention "your family," he might say "Can I talk to your family?" If you say "I will consider your investment in the future," he might say "Good, I'll call you again in six months." Finally, as James L. stays, do not feel bad or let him make you feel bad. The ONLY thing you could do that would be rude would be to be a "no-show"--to fail to show up for the appointment without cancelling it.

I would recommend something like this: Good morning/afternoon [name] I am writing about our upcoming appointment. Unfortunately, I must cancel the appointment for now. After discussing with my family, I have decided not to start new investments at this time. I hope to be ready in the near future at which time I will make another appointment. Thank you very much for your time and understanding. Sincerely [your name] I'm sure this happens relatively often and you should not worry or feel bad about canceling the appointment. The banker will understand. I hope this is helpful. Good luck!

Dear Mr/Miss.. In writing to inform you that for the moment, after a deep reflection with my family, i am no longer intentioned to go on with the investment we have been talking about recently. Please note that in the near future i will consider the investment again. I am sorry for the inconvenience. Please would you be so kind to cancel our appointment? Best Regards. Tony Ama.