SBVR 1.5 has an Accommodation Principle for elements of guidance that is worded like this (SBVR 16.3.2):

"An element of guidance whose meaning conflicts with some other element(s) of guidance must be taken that way; if no conflict is intended, the element(s) of guidance must be expressed in such a way as to avoid the conflict”.

This principle is a corollary of the second part of the severity principle, which says that elements of guidance in a body of shared knowledge must be interpreted as having all been expressed jointly and all being true.

Have a look at these elements of guidance:

You need concept structure to find out whether these two conflict. One way this can go is that you have a segmentation: a rental has a first driver and may have a second driver, and the first driver and second driver are both driver. Against this concept, the elements of guidance simply don't talk about the same thing, so they need not accommodate, but a third element of guidance is sorely missing: nothing states whether first drivers must have a valid driving license or not.

Another way this can go is that driver is the driver officially registered as the driver of a rental, and that you can optionally have a second driver. This way, the advice (the second statement) is equivalent to “Only nfirst] drivers need to have a valid driving license” which contradicts the business rule (the first statement). One of the statements has to accommodate, for example: