You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Carol Carter here.

ASSISTANT: How can I help you?

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

ASSISTANT: Give me a moment.

USER: Ok.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

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

ASSISTANT: Thank you for contacting us.