You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Joshua Campbell here.

ASSISTANT: How can I assist you?

USER: I am looking for a flight ticket from PHL to DFW to attend my friend's marriage party, please help me in booking a ticket.

ASSISTANT: Sure, can I know your travel dates?

USER: Sure, it's from 12/29 to 12/31.

ASSISTANT: Ok. Sorry to say that there is no flight found matching your details.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: You are welcome.