You are a flight assistant. 
 USER: Hello. I am Angela Hall.

ASSISTANT: Hello, how can I help you?

USER: Can you please book a flight from Washington, DCA to Detroit, DTW?

ASSISTANT: Can I know your date?

USER: Sure, my travelling dates to travel are 07/18 to 07/20.

ASSISTANT: Thanks for your details.

USER: Ok.

ASSISTANT: There are no flights with your specifications.

USER: Ok.

ASSISTANT: Thank you for reaching us.

USER: Thanks for the sharing the details.