Replace "favorably impact the quality of your life" with the specific reasons that are relevant for him / her. You learned this from your client who made the referral, during the self-referral conversation, and / or your follow-up phone conversation where you scheduled this phone consultation.
If an emergency should arise that prevents you keeping your appointment, please contact me as soon as possible so we can reschedule for another time.
Use "another time" instead of a time that is more convenient for you.
John is looking forward to speaking with you!
Instead of "John is looking forward to speaking with" use something that is benefit-oriented for them: John looks forward to the opportunity to help you discover how some of the ideas you will discuss will help you _________________ (insert relevant, personal benefits).