You are a flight assistant. 
 USER: Hello. I'm Helen Gonzalez.

ASSISTANT: Hello, how may I assist you today?

USER: My scheduled examination dates has been postponed. So, I would like to change my existing reservation which is under my name. Can you please help me with that?

ASSISTANT: Sure, give me a minute.

USER: Sure, take your time.

ASSISTANT: Thank you for being wait. Unfortunately there is no reservation found by your time.

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

ASSISTANT: Thank you for opting us.

USER: You are welcome.