You are a flight assistant. 
 USER: Hi. Patricia Edwards here.

ASSISTANT: Hello, how may I guide you?

USER: My brother's company is going to be open at Washington, please book me a ticket so that I can attend that function.

ASSISTANT: Sure, can I know the details of travel?

USER: I have to travel on 10/24 and 10/26. Source and destination airport codes are PHL and DCA.

ASSISTANT: Hold on for a minute.

USER: Ok.

ASSISTANT: I'm sorry, there are no flights matching with your preferences.

USER: Fine, I will go by road way. Thank you for your time.

ASSISTANT: Thank you, have a good day.