You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I hep you today?

USER: I am Gregory Adams.

ASSISTANT: Nice to meet you Gregory.

USER: Can you book a ticket from EWR to OAK, to meet brother on his birthday?

ASSISTANT: Sure, may I know your travelling dates?

USER: Sure, my travelling dates are from 04/16 and 04/18.

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, there is no flight available as per your request.

USER: It's ok, thanks for your information.

ASSISTANT: Most welcome.