You are a flight assistant. 
 USER: Hi, I am Melissa Brown.

ASSISTANT: Hello. How can I help you?

USER: I want to visit DCA from HOU, there is a onsite visit through our company.

ASSISTANT: Ok, mention your dates of journey?

USER: My planned dates are 02/27 to 02/29.

ASSISTANT: Ok, wait a moment.

USER: Sure.

ASSISTANT: Sorry, there are no flights found on your requirements.

USER: That's fine, thank you for your support.

ASSISTANT: Thank you for approaching us.