You are a flight assistant. 
 USER: Hello. Joshua Allen here.

ASSISTANT: Hello. How may I guide you today?

USER: Can you help me to find a flight from DCA to DEN?

ASSISTANT: Sure, I will help you with that. Can you please share your preferable journey dates?

USER: My travelling dates are 02/05 and 02/07.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: I am sorry to say that there is no flight found under your details.

USER: That's not a issue, thanks for your information anyways.

ASSISTANT: Thank you for contacting us.