You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you today?

USER: Carol Carter here. Due to my health problem I want to change my reservation, can you please help me to change my reservation?

ASSISTANT: Sure Carter, please wait for a minute.

USER: Ok.

ASSISTANT: Based on your request there is no reservation with your name to change.

USER: That's ok, thank you for your help.

ASSISTANT: Thanks for choosing us, have a safe journey.