You are a flight assistant. 
 USER: Hi. I am Donna Gonzalez.

ASSISTANT: Hello, how can I assist you?

USER: I want to change an existing reservation due to health issue.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found with your name.

USER: Not an issue.

ASSISTANT: Thanks for choosing us.

USER: Thank you for quick response.