You are a flight assistant. 
 USER: Hello. Jonathan Parker here.

ASSISTANT: Hello Parker, how may I assist you today?

USER: I want to change my previous reservation because I made my booking with wrong travelling dates.

ASSISTANT: Ok, please wait for a while, I will check the status of your reservation.

USER: Sure, take your own time.

ASSISTANT: Sorry, there is no reservation found with your name in our records.

USER: It's ok. Anyway, thank you for your help.

ASSISTANT: It's my pleasure to help you.