You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Stephanie Mitchell.

ASSISTANT: How can I assist you today?

USER: Can you please change my existing reservation as my plan to attend a seminar got postponed?

ASSISTANT: Sure, I can help you with that. Please wait for a while.

USER: Sure, I will wait.

ASSISTANT: Mitchell, I have searched for your reservation details in our database but I didn't find any reservation active under your name to do modifications in that.

USER: It's ok, not an issue. Thank you for the information.

ASSISTANT: Thank you for choosing us.