Hi. I am Gary Lee.
Hello. Good Afternoon Gary Lee. How may I serve you today?
I want to change my travelling dates in my recent reservation. Can you please help me out?
Sure, I will try my best to help you with that.  Can you please give me a minute to check your ticket status?
Ok, sure.
Sorry for the trouble which is caused to you, there is no reservation found with your name to modify the details.
Ok, fine thank you for checking.
My pleasure, thank you for consulting our agency.