You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I guide you?

USER: I want to change my existing reservation which is done recently due to some health issues, can you please help me in this?

ASSISTANT: Sure, I can help you. May I know your name to check your details?

USER: Thank you. Sure, my name is Jeffrey Brown.

ASSISTANT: Please wait a while.

USER: Sure, I will wait.

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, no problem. Anyways, thank you for your service.

ASSISTANT: Thank you for reaching us.