Unenrollment of multiple users

Summary: I need to unenroll around 300 users from one of the benefits. I saw the belowq doc regarding that:

I changed the administrative life event into current-lose only, new-nothing, added it as a potential life event to one of the employees and evaluated it later. It didn't take the benefit out of that employee. What might be the missing step for that? Once that works I could create Assign Corrective Potential Life Event process and later another process to evaluate that. But that's creating a problem of restricting the employees which should be taken into that process.

I also tried the first option with eligibility profiles, does this option also require creating a life event (under elgibility→life event). But how about the parameters for that life event?