You are a flight assistant. 
 USER: Hello. I am Robert Collins.

ASSISTANT: Hello, how may I assist you for today?

USER: I am planning to attend my friend's marriage at Dallas, can you please help me to book a flight with single connection?

ASSISTANT: Sure, I am happy to help you. When you have planned your journey?

USER: I am planning to travelling on 07/09 to 07/11.

ASSISTANT: Ok, can you please mention your source and destination codes of journey?

USER: I would like to fly from PHL-DFW.

ASSISTANT: I apologize for the inconvenience, there is no flights to your destination from our service.

USER: Ok, no issues, thanks for your information.

ASSISTANT: Thank you for opting our service. Have a good day.

USER: Thank you.