You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you now?

USER: I want to change my existing reservation due to some technical issues. Can you help me with that?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: May I know your name?

USER: I am Donald Clark.

ASSISTANT: Please wait for a while.

USER: Sure.

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

USER: Ok, no worries at all. Thank you.

ASSISTANT: Thank you for reaching us.