96 tercel check engine light

The check engine light came on in my 96 tercel. I got it diagnosed and found it was the O2 sensor. I replaced the O2 sensor but the light is still on. Does the light need to be reset or do i need to drive it around awhile for it to reset?

there is 2 o2 sensors there is one on the exhaust manifold and one after the cat. Usally the one on the manifold goes out first. What i would do it take the pos cable off the cat for about 5-10min and put it back on and that will reset the light. and if it comes on again get it checked and tell me what is says.