You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I want to travel from DTW to LAS to visit Las Vegas, can you please help me to reserve my ticket from DTW to LAS?

ASSISTANT: Sure, can I know the travel dates please?

USER: Ok, my dates of journey is from 07/28 to 07/30.

ASSISTANT: May I know your name please?

USER: Ok, my name is Edward Green.

ASSISTANT: Sorry, there are no flights on your dates.

USER: That's ok.

ASSISTANT: Thank you for approaching us.

USER: Thank you for your service.