You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Sandra Allen.

ASSISTANT: How may I aid you today?

USER: Due to my exams got postponed, I want to change my existing reservation. Can you please help me with this?

ASSISTANT: Sure, please be on hold.

USER: Ok.

ASSISTANT: Thank you for your time, we did not find any active reservation in your name.

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

ASSISTANT: Thank you for reaching us.