You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Can you please help me to book a flight to travel from SFO to LAS?

ASSISTANT: Sure, can you please mention your travel dates?

USER: I will be travelling on Mar 28th and 30th.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Any other requirements to be met?

USER: I want to depart in the evening time.

ASSISTANT: May I know your name please?

USER: My name is Virginia Allen.

ASSISTANT: Sorry, no flights found with your requirements.

USER: No problem, thank you for checking it.

ASSISTANT: Thank you for contacting us.