You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Assist me in changing my previous flight reservation. As I modified my travel dates.

ASSISTANT: Yes, can you tell me your name?

USER: Mary Jackson here.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: Ok, no problem. Thanks for checking.

ASSISTANT: Thank you for reaching us.