How do you change the fuel modulator on a 1997 Buick Riviera?

If you mean fuel pump module. You get to it from the trunk. lift out the carpet, their is an access panel with about 5 8mm bolts, front of trunk, pass side. You have have to crawl all the way into the trunk to get it out. Make sure the hood supports are stable, so you don't lock your self in the trunk !