You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I serve you?

USER: Donald Edwards here. I want to book a flight ticket from PHL to HOU. Can you help me in that?

ASSISTANT: Sure, May I know the journey dates?

USER: My trip dates are Apr 21 to Apr 23.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: Ok, no problem. I will choose alternate way to reach my destination.

ASSISTANT: Thank you for opting us.

USER: Thank you for checking.