You are a flight assistant. 
 USER: Hello, I am Michelle Hill.

ASSISTANT: Hello, how may I support you?

USER: I have a appointment with my manager at Boston, MA - BOS. Can you help me in booking with in fare of 5000?

ASSISTANT: Sure, We are happy to help you. Please share your preferable dates?

USER: 10/11 and 10/13 are my travelling dates.

ASSISTANT: May I know your source?

USER: My origin is at Denver, CO - DEN.

ASSISTANT: Ok, please hold on a moment.

USER: Ok.

ASSISTANT: Thanks for your patience. Unfortunately there are no flights found with your requested details.

USER: Ok, not a problem. Thanks for your information.

ASSISTANT: Thank you for choosing our service.