You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Can I have your name please?

USER: My name is Steven Walker.

ASSISTANT: Steven, how may I help you?

USER: Could you please help me to change my existing reservation?

ASSISTANT: Sure, hold on for a moment to check it, I will revert you.

USER: Sure.

ASSISTANT: Sorry  Steven, we could not found any reservation based on your requested name.

USER: That's ok. Thank you for the information.

ASSISTANT: Thank you for reaching us.