Hello, Donna Lopez here.
Hello. How can I help you?
 I want to do some changes in my existing reservation because I did not get the concert tickets, so planning to travel on another date, can you please help me?
Sure, please wait for a while.
Ok.
Sorry, we didn't found any reservation on your name. Do you want any other information please?
It's ok. No. Thank you for the information.
Thank you and have a nice day.