It is difficult unless you are one of the many appraisers who do very simple reports.
You have so many dependencies in reports, yet to remove identifying information you need to:
1. Change all identifying information, including data that could be used to find the property, such as GLA, lot size, GIS coordinates, MLS numbers, parcel numbers, etc..
2. Change all price and cost values.
3. Make sure all your data agrees.
4. Alter or replace all photos.
Goal:
Make a demo report that is representative of your reports, showing the techniques you employ.
Suggestion:
1. Pick up the property and move it to a different city. In fact, it can be an imaginary city that doesn't exist, call it "Phantom City." Don't worry if the landscape in the photos doesn't match the new location. Make all the corresponding changes to addresses.
2. Use photoshop or some tool to blur all photos with a landscape so that no one can pick up the original location from the photos.
3. Use low res jpg for your interior shots - and place the words "LOW RES DEMO" on top of each photo with some batch photo tool like IrfanView. In fact, use IrfanView to batch process all interior and exterior images, reducing resolution and placing "LOW RES DEMO" over all images.
4. For GLA and lot size, randomly add or subtract 10,20,30,...,100 sf to all GLA values. You can use the Excel function "randbetween" to randomly choose numbers between 1-10 and then multiply them by 10 and then choose a random number and multiply by -1 if it is odd or 1 if it is even. So, you will alter all GLA values by -100 to 100 sf.
5. Similarly alter all lot sizes.
6. Then alter all sale prices in a similar manner.
7. So, if you know how much you have altered the GLA and lot size, you can correspondingly alter the adjustments. You have altered the sale prices, so you calculate the difference between the sale prices, from that the total adjustment, subtract the adjustments from the GLA, and lot size changes and then find a place to put that difference - which could be split between additional adjustments on condition and quality.
And so on.
Notes:
1. If you want to show how good your photography is, create a separate demo.
a) Maybe you do drone photography - show an example from some house - without any address or location. Blur or alter the landscape to a certain extent.
b) Maybe you do very high quality professional photography - you can show that in the same way, removing or altering enough landscape so that a web program cannot easily find matches on the interiors or exteriors.
2. If you do good floorplans - especially CAD floor plans, make the necessary alterations in a couple of dimensions to change the GLA to match what you have in the report. Remove all other identifying information. Maybe salide a few interior walls around a bit.
3. If you have complex pricing models, then that will likely make your work much harder.
4. Try to deal with adapting the Cost and/or Income Approach to your changes. That can be murder.