Absence plan duration six months?

I'm trying to change the term of the plan to 6 months, it currently has the anniversary date, it only expires after 12 months, I need to reduce it to 6 months, how can I do it?

I'm trying to create a fast formula that validates this

There is an amended legislation in Mexico, which we need the tool to meet. It reinforces the period of 6 months, therefore, we need that for the behavior of the tool, it is possible to set a period of the plan with a period of 6 months. This can impact the business in fines because it is legislation.