A plumber can unclog a blocked toilet but may use the same tools available to homeowners. The only things necessary for simple clogs are a plunger and a toilet auger. However, more advanced pipe work may be necessary for major clogs that neither a plunger nor auger can reach.
To use an auger, thread the auger cord down the toilet drain, pressing and turning the handle so the drill bit turns and breaks its way through the clog. It may be necessary to pull the auger out slightly, breaking the clog into smaller pieces. Then, flush the toilet several times to remove the clog.