does the scan code have to cleared after cat converter replacement on 2000 Toyota Corolla

Code P0420 2000 corolla CE 1.8 ltr 4, 157K. O2 sensor 1 upstream replaced. After 500 miles, Code returned, shop says needs new Cat Conv. Done also. Does the scan code have to be manually cleared on this model or will it clear itself after repairs when drive cycle is met? How long is drive cycle? What does drive cycle require?

Asked by for the 2000 Toyota Corolla
Did you replace the 02 behind the converter as well? Yes the codes have to be cleared, can unhook battery neg. cable for a minute or so should do it. IF it is fixed that is. If code comes back replace the downstream sensor, if code comes back after that use better parts!