What needs to be done with error codes P2187, P2189 on 2006.5 Kia Optima EX?

Question

I have been getting the check engine light and have already replaced O2 sensors in bank I 1nd 2, the mechanic says that the other 02 sensors are OK. What do I need to have done to make this go away? The car only has 40,500 miles on it.