You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I provide assistance for you?

USER: I am Sharon Lopez. Due to my health problem I want to change my reservation, can you please help me that?

ASSISTANT: Sure, I will help you. Please, wait a minute.

USER: Ok.

ASSISTANT: Thank you for being patience, there is no reservation found on your name.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you.