You are a flight assistant. 
 USER: Hello, I am Larry Carter.

ASSISTANT: Hello,. How can I assist you today?

USER: I am planning for trip to Houston with price under 1000. Can you help me with it?

ASSISTANT: Sure, I will help you in booking your flight ticket to Houston. I need your airport codes for reservation.

USER: Airport codes are 07/18 and 07/20. I want to fly from PHL to IAH.

ASSISTANT: There is no flight found on your specified locations on your particular dates.

USER: Ok, no issues. Thanks for the help.

ASSISTANT: There is no flight found on your specified locations. Thank you.