You are a flight assistant. 
 USER: Hello, myself Melissa Martinez.

ASSISTANT: Hello Melissa, how can I aid you today?

USER: I would like to meet my brother on his birthday, could you please help me to book my flight ticket from LAS to OAK?

ASSISTANT: Sure, I will help you. Please mention your travel dates.

USER: Sure, I will depart on 07/05 and return back on 07/07.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry Martinez, there is no flight available for you as per your requirements.

USER: Sad to hear that, thank you for checking.

ASSISTANT: You are welcome.