If that’s the case, this is what I would do.
- Study hard for the exam
- Take it as normal, see how you feel about it
- Go to advising appointment and examine options with advisor; if you feel like you aced the exam, maybe you don't have to drop. If you aren't sure or know you didn't do well, you may decide to drop.
Can you not just drop on LionPATH? I can understand why they’d want you to talk about it first but I think students do have the capability to add and drop at will on LionPATH.
Edit: Perhaps there’s both a LionPATH and in-person component. Website is unclear. If the advisor said you could do it during a walk-in they’re probably right.