newbie, how does a 2-call system work exactly?  Thanks in advance

This is probably better addressed in the Newbie area, but since I'm here...

When you arrange your date the provider will give you directions to her general location, such as the hotel, but not the room.  Then when you reach that point she will tell your the room number.

You're welcome.
TS Jamie

Good question - but what is the purpose of the second call?

I wondered the purpose of the second call too. After all, I could call you from my house, you give me general directions, I call from my house 30 minutes later and I say "I am here", you know give me the apt/hotel room. I still have the info?? Unless they are watching you from a window/parking lot etc. and sizing you up as legit or not.