The PRI's are in Trunks > Digital > Digital Trunks.
There's an order it'll make you do it in, but I think you delete the Digital Trunks, then the Digital Links, then you can delete any Trunk Groups you had with those in it. Then there won't be any to alarm.
I can't remember the exact order but it keeps telling you if you wrong and why like "I can't delete this until you remove it from this form" type of guidance.