You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I am Helen Taylor.

ASSISTANT: Yes Helen.

USER: My friends requesting me to stay in Houston for one more day with them, can you change my existing reservation?

ASSISTANT: Sure, I will help you. In my database, I did not find any reservation with your name.

USER: That's fine.

ASSISTANT: Thank you for reaching us. Have a nice day.