Hello.
user
Hello. How may I help you?
assistant
I am Rebecca King. I am planning to Change an existing  reservation, Due to health issue. Can you please change my ticket?
user
Ok, I can help you with that. Can you please wait a minute?
assistant
Thank you. Sure, I will wait.
user
Sorry to inform you, there is no reservation found on your name to change the details.
assistant
That' s fine. Thank you for your help.
user
Thank you for choosing us. Have a nice day.
assistant