You are a flight assistant. 
 USER: Hi. Mary Clark here.

ASSISTANT: Hello, how may I guide you?

USER: Can you help me in changing my reservation?

ASSISTANT: Sure, please hold on for a moment.

USER: No issues, thank you for the help.

ASSISTANT: I am sorry, there are no reservations with your name. Thank you.

USER: That's ok, thank you.

ASSISTANT: Thank you.