This article should help: How to Add, Replace, & Remove disks
You should be able to remove device(s), one node at a time, restart the node (careful about impact of coldstart on CE) wait for migrations to rebalance (and readd the data, distributing it across the remaining device(s)) and then proceed to the next node. For EE, the restrictions of only being able to remove the last device(s) may not be necessary anymore (which then lets you take advantage of fast restart).