You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help 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, may I know your name?

USER: Sure, my name is Barbara Lee.

ASSISTANT: Thank you. Please wait, let me check your reservation status in our database.

USER: Sure, I will wait.

ASSISTANT: I am sorry, there is no reservation found under your name in our database.

USER: Ok, no problem. Anyways, thank you for your service.

ASSISTANT: You are welcome and thank you for choosing us.