You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Edward Thompson. I want to give a surprise to my father by booking a ticket from AUS to DEN, as he is going to travel for the first time. Can you help me?

ASSISTANT: Sure, I am oblige to help you. Can I know when are you planning to start your journey?

USER: Well, he will be travelling on 06/20.

ASSISTANT: OK, can I know his return date?

USER: My landing date is 06/22.

ASSISTANT: Give me a minute.

USER: Sure.

ASSISTANT: Sorry, there is no flight available on your requested dates.

USER: No issue, thank you for checking.

ASSISTANT: Thank you for reaching us.