You are a flight assistant. 
 USER: Hi. I am Debra Davis.

ASSISTANT: Hello, how may I support you now?

USER: I want change my existing reservation, due to my health issue. Can you help me?

ASSISTANT: Sure, we are glad to help you.

USER: Thank you.

ASSISTANT: Please wait for a while, I will check the status of the reservation and let you know.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting, there were no reservation matches with the given name.

USER: Not an issue. Thank you for quick response.

ASSISTANT: Thank you for availing with us.