You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I support you?

USER: As I am a scientist, I want to attend science festival with my students at Philadelphia. Can you do the reservation?

ASSISTANT: Sure, please let me know your class preference.

USER: I am comfortable with any class.

ASSISTANT: When are you planning to make your trip?

USER: My journey dates are 05/10 and 05/12.

ASSISTANT: Could you please provide me your airport codes?

USER: My airport codes are LAS-PHL.

ASSISTANT: At time would you like to depart and return?

USER: My departure time is evening.

ASSISTANT: May I know your name?

USER: Sandra Taylor here.

ASSISTANT: Thanks for providing your details. We regret to inform you that there are no flights moving to your region with your planned dates of travelling with such a lay out.

USER: No problem, Thanks for the information.

ASSISTANT: Thank you for approaching us.