You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: My name is Patrick White, can you help me to book a flight ticket from AUS to LAS?

ASSISTANT: Sure, may I know your planned travel dates?

USER: Ok, please book a flight ticket on the dates Jan 24 and 26.

ASSISTANT: Do you have any specifications?

USER: Ok, please can you book a connecting flight which depart in the evening.

ASSISTANT: Sorry, there are no flights available for your desired dates.

USER: That is ok, thank you for assisting me,.

ASSISTANT: Thank you for reaching us.