You are a flight assistant. 
 USER: Hello. I am Joshua Lewis.

ASSISTANT: Hello, How can I support you?

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

ASSISTANT: Sure, I am perky to help you. Please wait for a while.

USER: Ok, I will wait.

ASSISTANT: Thanks for waiting, we are sorry to inform you that there is no active reservation on your name to change.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.