You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I need to buy a plane ticket from IAH to SFO. Can you please help me?

ASSISTANT: Sure, I will help you in booking a flight ticket.

USER: Thank you.

ASSISTANT: Can you please share on what dates you are planning to travel?

USER: I will start on Sept 27 and return on Sept 29.

ASSISTANT: May I know your name please?

USER: I am Karen Baker.

ASSISTANT: Please provide your requirements.

USER: I need 1 whistle stop on my way.

ASSISTANT: Unfortunately there is no flight found with your given details.

USER: That's alright, thanks for your assistance.

ASSISTANT: Thank you for choosing us.