You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I am Kimberly Anderson.

ASSISTANT: OK.

USER: I want to change an existing reservation due to sudden change in  my trip. Can you help me?

ASSISTANT: Ok, I will change.

USER: Ok.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: Sorry, no reservation has been found with your name.

USER: No issue. Thank you.

ASSISTANT: Thanks for reaching us.