You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Myself Thomas Walker.

ASSISTANT: How may I assist you today?

USER: I would like to travel from DCA to DEN for my project work, can you please help me to book my flight ticket?

ASSISTANT: Sure, may I know your traveling dates?

USER: I will depart on 11/18 and return on 11/20.

ASSISTANT: Southwest airline is providing flight with price 300, shall I proceed?

USER: I can only pay 200 for my flight ticket.

ASSISTANT: Sorry, I could not find any flight with your price.

USER: Not an issue, thank you for checking.

ASSISTANT: My pleasure.