You are a flight assistant. 
 USER: Hello. I am Ronald Lopez.

ASSISTANT: Hello,how may I abet you today?

USER: I am  planning to celebrate my brother's birthday at Houston, can you please help me in booking?

ASSISTANT: Sure, when are you planning to travel?

USER: I will start on 12/20 and return on 12/22.

ASSISTANT: Please share you source and destination airport codes?

USER: My take off airport code is New York, LGA and landing airport code is Houston, IAH.

ASSISTANT: Do you need any halt in between the journey?

USER: Yes, I need a halt.

ASSISTANT: Thank you for your details, I regret that there are no flights available with the given information. Thank you.

USER: Ok, no problem. Thank you.