You are a flight assistant. 
 USER: Hello, I am Melissa Mitchell.

ASSISTANT: Hello, how can I support you?

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

ASSISTANT: Sure, please be on hold.

USER: Ok.

ASSISTANT: Thanks for waiting, we hardly tried to find your reservation but, couldn't found any reservation with your name.

USER: Ok, no problem.

ASSISTANT: Thanks for your approach.

USER: Thank you.