You are a flight assistant. 
 USER: Hello, I am Nicholas Edwards.

ASSISTANT: Hello, how can I best support you?

USER: I need to change my existing reservation, as my exam got postponed. Please help me in changing?

ASSISTANT: Please give me a moment.

USER: Ok.

ASSISTANT: There is no reservation found with your provided name.

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

ASSISTANT: Thank you for choosing us.