You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Ronald Campbell.

ASSISTANT: How can I help you?

USER: I would like to go for holiday trip to Detroit, can you please provide me a ticket?

ASSISTANT: Sure, I will help you for booking. Can you please provide me your travelling dates?

USER: I am travelling on these dates 02/07 and 02/09.

ASSISTANT: Ok, may I know your airport codes?

USER: I am flying from OAK to DTW.

ASSISTANT: Ok, give me a moment.

USER: Sure.

ASSISTANT: Sorry, there is no flight is available for you.

USER: Ok no problem, thank you for your services.

ASSISTANT: Welcome.