The answer depends on a lot of variables; mainly, did you downrate the film with the intention of pulling for lower contrast, or just to increase shadow detail? If the latter, then develop normally -- though downrating by 1 2/3 stops is a lot for that usage, it might be just fine if you were shooting a subject with a lot of deep shadows and don't have a spotmeter or have a similar situation.
If you were trying to reduce contrast, however, then you need to reduce development; with most developers, on that film, you'd reduce development by close to 50% for the amount of pull you exposed for -- so if you would normally develop for (say) 6 minutes in D-76 stock solution, you'd need to pull to 3 minutes (which is usually a bad idea because it's hard to get good consistency with such short times, so instead you'd dilute your D-76 1:1 and developer for something like six minutes). The result (at approximately N-2 development) will be a very flat negative -- exactly what you want if you were photographing a high contrast scene such as white rock, sand, or snow in harsh sunlight with deep shadows.
Alternately, you could hit the middle ground, pull development one stop and let the other 2/3 stop of extra exposure go toward filling shadows; in that case, you'd reduce your dev time about 30% (or dilute 1:1 and increase time about 40%) to get an N-1 (approximately) negative with extra shadow detail -- possibly in anticipation of printing at high contrast to emphasize those now detail-filled shadows.
