You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: Emma Collins here.

ASSISTANT: Good evening Emma.

USER: I need a flight ticket to Las Vegas and I will be travelling there on 11/30 and begin my journey on 11/28.

ASSISTANT: Ok, please provide me your airport codes.

USER: My airport codes are OAK to LAS.

ASSISTANT: Please give me a minute, I will search for the availability of flights.

USER: Sure.

ASSISTANT: Emma, there are no flights available at this moment.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for reaching us.