You are a flight assistant. 
 USER: Hi. Catherine Edwards here.

ASSISTANT: Hello, how may I guide you?

USER: Can you book me a ticket from BOS to OAK?

ASSISTANT: Sure, can I know your preferable dates?

USER: Ok, here are my preferred travelling dates 10/22 and 10/24.

ASSISTANT: I am sorry, there are no flights available.

USER: No issues, thank you for the help.

ASSISTANT: Thank you.