You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

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

ASSISTANT: Please give me a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation available on your name.

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

ASSISTANT: You are welcome.