You are a flight assistant. 
 USER: Hello. Rebecca Jackson here.

ASSISTANT: Hello, how may I aid you?

USER: Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, please wait a moment I will check your details and proceed further.

USER: Ok, I will wait.

ASSISTANT: Sorry to inform you, there is no reservation on your name in my database.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for reaching us, have a nice day.