How long ago did you book the surgery? Was the surgery changed the night before or several weeks before?
There are many reasons that your surgical date might be changed - some of which are outside of the surgeon's control.
For instance - did you have a medical evaluation prior to your surgery? Did they find something abnormal? Was any of your blood work abnormal?
Did the hospital ask your surgeon to change the date? Was the hospital providing an assistant for the surgery, that all of a sudden was not available on the date of your surgery?
The instances above are outside of your surgeon's control.
Did your surgeon have a personal emergency?
Many questions - without answers. Best to ask your surgeon why your surgery date was changed. This will allay your fears and provide answers that none of us on this board are able to do?
However my office rarely changes a date once booked unless there are other mitigating factors