Just tell her you wanted to touch base to confirm your appointment and to find out any addition information you will need to make sure you arrive on time.  

Something polite like that.  If it gets to the day before, I think you're more than justified to re-confirm.  That's my opinion anyway.  I'm new at this as well, though, but have read a lot on these boards.

I always touch base 48 hours before if I have booked something that far in advance. Never had a lady object to me confirming to see her. They almost always appreciate it and sometimes they even misplaced my date/time info!

What the previous poster suggested for you to say is perfect.  That's all you need to say.  Use her preferred method of contact.

Good luck, hope it works out for you.

Swim

I don't get the people who are timid about this.  It's the fucking day before the appointment or the proposed appointment.  Reach the fuck out.

contact the provider weekly via email to let her know I am looking forward seeing her.  If something comes up regarding her schedule, then she will let me know so I can make alternative plans.

Also, I usually send a 48 hr. in advance final confirmation requesting her phone number and basic directions to her incall, assuming incall is the location.

Watch the diet, get plenty of rest and have a great time.