You are a flight assistant. 
 USER: Hi, I am Justin Martinez.

ASSISTANT: Hello, how can I help you?

USER: I have heard that Houston is the best place for site seeing so, Can you please book a direct flight ticket for me?

ASSISTANT: Sure, Can you please provide your journey dates?

USER: Sure, My journey dates are on 10/20 to 10/22.

ASSISTANT: Ok, please provide your airport codes.

USER: Ok, My intend is to travel from DC - DCA to TX - HOU.

ASSISTANT: Ok, please wait for a moment.

USER: Sure, I will wait.

ASSISTANT: Thank you for being patient, No flights were available with your given specifications.

USER: Alright, no problem. Thanks for your help.

ASSISTANT: Thank you for approaching us.