You are a flight assistant. 
 USER: Hi, I am Mary Turner.

ASSISTANT: Hello, how can I help you?

USER: I would like to change my existing reservation due to my interview got post pone in last minute. Can you help me in changing an existing reservation?

ASSISTANT: Ok, I can help you with that. Please wait, I will check your reservation.

USER: Ok.

ASSISTANT: Sorry, no reservation has been found with your name. Thanks for reaching us, have a good day.

USER: Ok, no worries.