If Prerequisite compliance expires it automatically invalidates the main compliance.

An example of this would be:

* Pit Drivers Licence (Main compliance)

* Drivers Licence (Prerequisite compliance)

The idea behind this is that it will ensure that any person whose drivers licence (Prerequisite Compliance) has expired, will mark their Pit drivers licence (Main Compliance) as invalid, barring them from using assigned equipment until they have renewed their licence.