You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Kimberly Thomas.

ASSISTANT: How may I help you?

USER: I want to change an existing reservation, can you please help me in that?

ASSISTANT: Sure, I am here to help you. Please wait, let me check your reservation status. Sorry, there is no reservation found under your name in our database. Thank you for contacting us.