Recoding a Recoded Variable

Friends, I have transformed 380 "occupation" variables into a new variable (occnew) with just 22 categories (such as skilled labor, professionals, domestic labor, etc.). I find now that I made a couple of crucial mistakes when inputting the data but can't figure out how to correct it. In other words, I put a couple of occupation codes into the wrong categories. How can I revise my occnew without having to re-input the 380 occupation variables? I haven't been able to locate any threads on this issue. Any ideas? Thanks.
I would create a new variable occnew2. Make it equal to the occnew unless your original variable = one of the ones you misclassified.

So occnew2=occnew unless occoriginal = #, #, or # (the ones you made a mistake on). If so, then #1 becomes x, #2 becomes y, etc.

It will probably be a pretty long nested statement, but should work just fine as long as you think the logic out properly.