In general, best practice is to not change the baseline schedule one it has been set. There will be deviations that are the changes.
For your own tracking purposes as PM, you may want to have an unofficial copy of the schedule that shows the modifications. Another way of handling this situation is to start new plans for each change -- it will depend on how all the pieces fit together and only you can decide once you have examined all the scheduling required to meet the changes. On some projects its possible to schedule the changes after the main schedule completes and on others it would be inefficient.
Sometimes if there are a large number of changes with significant scheduling impact, it might be worth considering the creation of a new baseline.