You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Christopher Green.

ASSISTANT: Ok.

USER: Please book me a ticket from IAH to IAD to meet my family.

ASSISTANT: Sure, will you mention your travelling dates please?

USER: I have planned to travel on 02/24 and 02/26.

ASSISTANT: Please give me a moment.

USER: Ok, I will wait.

ASSISTANT: Thanks for waiting, there is no flights found under your preferable details.

USER: Ok, no problem. Thank you.

ASSISTANT: Welcome, have a great day.