You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: Michael Smith this side, can you help me to book a ticket from OAK to LAS?

ASSISTANT: Sure, I will help you, please provide me your travelling dates.

USER: I am looking to travel on the dates 11/27 and 11/29.

ASSISTANT: Ok, give me a moment.

USER: Sure, take your time.

ASSISTANT: Sorry, there is no flight available for you.

USER: No issues, thank you.

ASSISTANT: Welcome. Thank you for choosing us.

USER: You are welcome.