You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Rachel King.

ASSISTANT: How can I assist you?

USER: As my exam is postponed, I want to change my existing reservation. Can you help me?

ASSISTANT: Sure, I will help you with this.

USER: Thank you.

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

USER: No issue, thank you.

ASSISTANT: Thank you for contacting us.