Dongguan social security in the month of the reduction in the month of the effective?

The company's employees are not fixed, there are times when employees will leave, there are also new employees to start. Whether it is entry or exit, and our financial will have a relationship. In addition to the wages involved here, there will be involved in social security issues. Does the reduction in force take effect in the same month or the following month? Here there is a time limit, the specific instructions are as follows.