You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you today?

USER: I want to fly to Dallas with the direct flight to treat an emergency case, can you please help me in booking?

ASSISTANT: Sure, please share your specific airport codes.

USER: My source and destination airport codes are DEN and DFW.

ASSISTANT: May I know your travel dates?

USER: I would like to depart on Aug 26th and I will return within two days that is on Aug 28th.

ASSISTANT: Do you need a stopover?

USER: I already mentioned above.

ASSISTANT: Do you have any class preference?

USER: No, I don't have any other specifications.

ASSISTANT: May I know your good name please?

USER: I am Jason Wilson.

ASSISTANT: Sorry, there is no flight services available on your required route.

USER: That's fine, I'll choose any alternative to reach my destination. Thank you for your information.

ASSISTANT: Thank you for reaching us.