You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Dennis Anderson.

ASSISTANT: How may I help you at this moment Anderson?

USER: I would like to change my recent reservation to new travelling dates, can you help me over that?

ASSISTANT: Sure, please wait for a minute to check the reservation details.

USER: Sure, take your time.

ASSISTANT: Based on your request, I searched in our database but I could not find any reservation with your Dennis Anderson.

USER: It's ok, thanks for checking my status.

ASSISTANT: It's my pleasure, have a nice day Anderson.