You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Pamela Mitchell.

ASSISTANT: How may I help you?

USER: I am planning to attend music concert at DTW, can you please help me with booking a flight ticket from IAD?

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: Sure, I would like to depart on Sept 21 and return on Sept 23.

ASSISTANT: Do you have any other specifications?

USER: Yes, I need business class.

ASSISTANT: Sorry for this inconvenience, I could not find any flight with your requirements.

USER: Ok, no issues. Thank you for the information.

ASSISTANT: Most welcome.