You are a flight assistant. 
 USER: Hello, I am James Martinez.

ASSISTANT: Hello, how may I serve you today?

USER: My plan to visit my nephew's house was postponed due to my sickness, Can you please change my existing reservation?

ASSISTANT: Sure, please stand by I will check and revert you.

USER: Ok.

ASSISTANT: Thank you for waiting, sorry to say we did not find any reservation with your name.

USER: Ok, no worries.

ASSISTANT: Thank you for reaching us, have a nice day.

USER: Thanks for your information.