You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: I am Andrew Jones want to travel to LAS from IAD, can you please help me in booking?

ASSISTANT: Sure, may I know your travelling dates?

USER: I want to start my journey on Oct 19th and return on Oct 21st.

ASSISTANT: Sure, may I know your connection limit?

USER: I do not have connection limit.

ASSISTANT: Do you have any other preferences?

USER: I need to depart in the evening time.

ASSISTANT: There are no flights available on your request.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.