You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am planning to attend my friend's wedding at Dallas. Can you please book me a flight ticket from ORD to DFW?

ASSISTANT: Sure, I am here to help you in booking. Can you please share your travel dates?

USER: My planned journey dates are May 30 and June 01.

ASSISTANT: Do you have any specification?

USER: My depart time should be evening.

ASSISTANT: Sorry, no flights are available on your preferable travel dates.

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

ASSISTANT: May I know your name?

USER: I am Nicholas Walker.

ASSISTANT: Thank you.

USER: Thank you.