You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you today?

USER: Due to changes in my plan, I need you to change my recent booking.

ASSISTANT: Sure, please share the name on which you have done you reservation.

USER: I am Jack Hall.

ASSISTANT: Kindly wait for a while.

USER: Sure, I will stay online.

ASSISTANT: We don't have any reservation with the name of Jack Hall to make changes.

USER: That's ok. Thank you for trying to help me.

ASSISTANT: Thank you.

USER: You are welcome.