You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I want to change my reservation as my plan to go for trekking got postponed. Can you help me?

ASSISTANT: Sure, I am here to help you with that, can I know your good name to proceed further?

USER: I am Dennis Anderson.

ASSISTANT: Sorry to inform you that there is no active reservation on your given name.

USER: That's Ok, thanks for your response.

ASSISTANT: Thank you for contacting us.