You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Katherine Miller here.

ASSISTANT: How can I help you today?

USER: Could you book my ticket in a direct flight?

ASSISTANT: I am gleeful to help you with that, can you share me your planning dates?

USER: My trip dates are May 28 and May 30.

ASSISTANT: Do you have any preferences?

USER: No.

ASSISTANT: I need to know your nearest airport codes?

USER: I will be travelling from MSP to OAK.

ASSISTANT: Sorry to say this, no flights are available on your travelling dates.

USER: No problem, thank you.

ASSISTANT: Thank you for opting us.