You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you today?

USER: I have planned a trip in the month of April to enjoy my summer holidays in the Mountains park, can you book a ticket for me?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Could you please provide your preferable dates of travelling?

USER: I would like to take off on 04/22 and arrival back on 04/24.

ASSISTANT: Ok, may I know your origin and destination airport codes to proceed further?

USER: Yes, the nearest airport codes that I am preferring is OAK to LAS.

ASSISTANT: Please wait a moment to check the flights availability and I will revert back to you.

USER: Sure, take your time.

ASSISTANT: Sorry to inform you that, there are no flights available in your travel locations with your requested dates of travelling.

USER: No issues with that one, thanks for your search.

ASSISTANT: Thank you for reaching us, have a great day. May I know your name for reference purpose?

USER: Sure, I am Jessica Baker.

ASSISTANT: Ok Jessica, thank you.

USER: Most welcome.