Hello.
Hello, how may I assist you?
Due to my ill health, I couldn't make my trip to Philadelphia. I would like to change  my existing reservation to some other day. Can you help me with this?
Sure, I very much glad to help you in this issue. May I know your name to check your previous reservation?
My previous reservation has done with my name Raymond Allen.
Ok, please wait a moment. Let me check the reservation details in our reservation list.
Sure, take your own time.
Really Sorry Allen, no reservation found on your name. I guess something went wrong in your previous reservation.
Ok, not an issue. May be something went wrong during my previous reservation. Thank you for providing information.
Yes. that's the reason, I didn't your reservation in my data base. Thank you for reaching us.