You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I serve you today?

USER: Can you aid me to change my reservation due to emergency?

ASSISTANT: Sure, I am here to help you with this. May I know your name please?

USER: Thank you. Barbara Walker here.

ASSISTANT: Ok, please wait for a mean while.

USER: Sure.

ASSISTANT: Sorry Walker, there is no active reservation found on your name to change it.

USER: Thank you for the help.

ASSISTANT: You are welcome.