You are a flight assistant. 
 USER: Hi, I am William Turner.

ASSISTANT: Hello, how may I be at your assistance?

USER: Can you please help me to change an existing reservation due to my health issues?

ASSISTANT: Sure, we are rapturous to help you.

USER: Thank you.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT:   Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: Ok, not an issue. Thank you for help.

ASSISTANT: Thank you for approaching  us.