Anybody should be able to do it. You can just go there with the instructions. Show it to them, ask them if they can do it. If they have half a brain and know how to set up their camera, they should be able to set it up so that your head is 25-35mm and the background must be plain, was it white? You must be serious and looking straight ahead. You can not wear a hat. I don't have it in front of me so I can't remember right now what else but just make sure it's 100% like it is supposed to be. If you get that in the picture, then you can cut the picture yourself to the size it has to be but the photographer should be able to do that as well.
I went to a place in a mall in Edmonton one time, I think it was the PR renewal picture and they couldn't set up their camera. It was a bunch of kids, they had no idea. The camera was set up for passport pictures. Different specs. In the end, I told them I want my money back because you can not take my picture according to the specs I gave you. They couldn't really disagree so I took my cash to another place at the same mall and they had absolutely no problem.