You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Can you please reserve me a flight ticket from DEN to IAH to go for holiday trip?

ASSISTANT: Sure, may I know your class preference please?

USER: I prefer an economy class for my journey.

ASSISTANT: Tell me your name please?

USER: I am Alexander Nelson.

ASSISTANT: Now share your travel dates please?

USER: My planned journey dates are Aug 19 and Aug 21.

ASSISTANT: Do you have any other preferences?

USER: I need a stopover in between my journey.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: Sorry there no flights available with your flight details.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Thank you.