You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Shirley Campbell.

ASSISTANT: How can I help you at this moment?

USER: I want to change my existing reservation due to my exam dates has been postponed. Can you please help me with this?

ASSISTANT: Sure, I am here to help you. Please give me a moment to check your reservation status.

USER: Sure.

ASSISTANT: Shirley Campbell, there is no active reservation found under your name in our database.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: Thank you for contacting us.