To apply a special situation to a worker who is going to perform a different job than the rest of the employees, what we have to do is go to the employee's details:

And once inside, go to the "Special situations" drop-down menu. Make sure you have the "See all" option checked:

There you will see all the special situations available to apply to the employee. You will simply have to select the one that applies to the worker in question and click on the "Apply changes" button:

In this video, we explain what special situations are and why and how they are used: