You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: I need to change my reservation due to urgent meeting, can you help me?

ASSISTANT: Sure, I will help you with that. May I know on which name your reservation was made?

USER: David Martin.

ASSISTANT: Please wait for a moment, while I check for your reservation.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name in our system data.

USER: That's ok. Thank you for your help.

ASSISTANT: Thank you for visiting us, we hope see you again.