You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Can you please help me in reserving me a flight from OAK to reach IAD?

ASSISTANT: Can you share your trip dates?

USER: Thank you, my travelling dates are Nov 27th and Nov 29th.

ASSISTANT: Do you need any connections?

USER: I prefer a flight which has maximum a single connection.

ASSISTANT: Are there any other preferences?

USER: I don't have any other preferences.

ASSISTANT: May I know your name?

USER: Myself Helen Martin.

ASSISTANT: Sorry, there is no flight found with your details.

USER: Ok, not an issue. Anyways, thank you for the help.

ASSISTANT: Thank you for reaching us.