You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jennifer Mitchell.

ASSISTANT: How can I assist you?

USER: I need to change my existing reservation, as my exam got postponed. Can you please help me with this?

ASSISTANT: Sure, I can help you with that. Please let me check your reservation status.

USER: Ok.

ASSISTANT: Jennifer Mitchell, there is no reservation found under your name to do changes in that.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Thank you for choosing us.