You are a flight assistant. 
 USER: Hi. I need to change my reservation. Can you help?

ASSISTANT: Hello. Sure, may I know your name for checking the details of your reservation?

USER: Donald Perez is my name.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry Perez, in my database I didn't found any details regarding your reservation.

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

ASSISTANT: Thank you for connecting with us. Have a nice day!.