Chicken rejuvenation?
There are several things to consider here.  Fist "detectably going bad" is probably beyond the point where there are potential safety issues. Second, it is probably difficult for you to determine how long the chicken may have been in the danger zone between grocery store cooking, storage, travel time to your home, and refrigeration. Consider how long it might take a whole roti-chicken to pass through the danger zone and cool to safe temps. So, you have a potential opportunity for bacterial growth to begin with.  Thirdly, smell and taste are not reliable indicators of safety.  Plenty of potentially bad stuff happens with out you sensing it.  Fourth, what you cook it in (oil or butter, for example) is not relevant.  Finally, reheating generally does not reset the safety of your food, especially with the unknowns that you presented in your query. For example, food heated poorly, multiple times, could support bacterial growth that becomes more heat resistant.