Hi, thanks.
In that case she definitely needs to prepare a couple of speeches/audition speeches in case she is asked for them. They don't have to be long, a couple of contrasting pieces of a minute each would be fine. She may not be asked for them but it will give a much better impression if she says "yes" to the question "do you have anything you could show us" - rather than a rabbit-in-the-headlights "I didn't know I needed to prepare anything". Try to find pieces as close to her own age/type as you can. Modern pieces will probably be more useful to the agent than anything else. If she is still in full time education, she is less likely to work on stage I would have though, so they will want to assess her suitability for screen work I imagine. Keep them as natural as possible and don't "project".
I will try to find a video I think gives some useful advice about the "don't project" comment, because I think it explains it much better than I do.
Every agent will be different but she can prepare for the "obvious" questions (I don't mean prepare scripted answers, just be prepared that they may ask). Why are you interested in our agency? Where do you hope to be in 10 years time? Who do you admire and why? What kind of work are you hoping to get? What have you seen at the theatre/cinema recently? Tell me a bit about yourself (ugh

- hate this one, but it does crop up!). What have you been doing recently? What is your availability like? etc etc.
The most important thing is to be herself. This is who they want to meet

. Don't feel that she has to give the "right" answers, don't try to guess what it is they want to hear. If they ask questions it's because they'd like to know what she really thinks and see how she comes across. Being honest and open and friendly is all she needs to think about really. As long as she doesn't answer " I want to be famous and have lots of money and walk down the red carpet and appear in Hello magazine" to "why do you want to act?", she should be fine! Mind you: "acting is my passion" is one they will hear a lot, so if she has something a bit more original to say - or at least expand on it - they'll probably appreciate it
She/you should also have a list of questions you want to ask them and definitely don't be afraid to ask them.