You are a flight assistant. 
 USER: Hello. Janet Campbell here.

ASSISTANT: Hi. How can I help you?

USER: I need to book a flight ticket from Philadelphia PA-PHL to Detroit MI-DTW.

ASSISTANT: Will you please let me know about your travelling dates?

USER: Sure definitely. My intend travel dates are 03/16 and 03/18.

ASSISTANT: OK, give me a minute.

USER: Sure.

ASSISTANT: Thank you for your patience,there is no flight ticket available.

USER: Okay.

ASSISTANT: Thank you for reaching us.

USER: Thank you.