Yes you can if you follow the above advice but as Warren1 said WHY. The cost saved will not pay for the trouble calls later.
I have a customer where this was done in an apartment complex. Most of the residents who use computers there are having problems from monitors that will not go full screen to lost data and very slow response times. The owner will not pay for ugrading the neutrals, wants me to bill the outstate electrician who built them. That company will not pay for that. The tenants are not going to pay for it either. Can't fix the problem without repulling the feeders. It a no win situation. It may go to a lawsuit. With more and more electronic items going into houses,apartments, and other places this problem will just get worse. Downsizing a neutral is not worth the hassle now when you justify to the inspector, or later when problems occur.
