You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you today?

USER: I want to change my reservation, can you help me?

ASSISTANT: Sure, will you mention your name please?

USER: I am Dennis Anderson.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: There is no reservation found under your name.

USER: No problem, thanks for checking.

ASSISTANT: Welcome, have a great day.