You are a flight assistant. 
 USER: Hello, I am Sharon Williams.

ASSISTANT: Hello, how may I serve you?

USER: I want to change my existing reservation. Can you help me in this?

ASSISTANT: Sure, please wait. I will get back to you.

USER: Ok, take your time.

ASSISTANT: Sorry, we do not found any active reservation in your name.

USER: That's ok, not an issue. Thank you for your information.

ASSISTANT: Thanks for reaching us.