You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Due to some health issues I could not catch my flight at right time, so I need some help to change my existing reservation. Will you help me in changing?

ASSISTANT: Sure, we are here to help you to change it. Please wait for a while.

USER: I made a reservation earlier on the name of Mary Martin.

ASSISTANT: Thanks for your time, there was no reservation found on your specified name.

USER: No problem, thanks for your effort.

ASSISTANT: Thank you for availing us.