How to make PTO (Vacation) request for overnight?

I know how to make a PPTO request since I've done it many times before. I call out, then make a request for the day the shift that I missed would have started. So if I wanted to not come in on Saturday, I would just submit the PPTO request for Saturday and it would be automatically approved. Even though most of my shift cut into Sunday morning. I assumed the same was true for PTO but somebody told me that PTO requests had to be done differently. I know that PTO requests have to be made at least before the schedule is finalized for the day you want to call out, but I was told that if I want to make a PTO request, I would have to put in 2 hours on the day I want off, and then 6 hours for the next day. I have never seen this on the Wire or anywhere else so I just want to make sure that this is the correct way to do it. I thought that if I wanted a day off I would just put in 8 hours like I would if it were PPTO. But according to my coworker that's wrong. So I want to have 2 days off in July. On a Saturday and Sunday. How exactly do I make this request?