Partitions are set on a user level. See User ID.
When partitions are enabled and a partition is selected, you may only control and record data for the channels included in the partition, with the exception of parking and unparking channel parameters or playing back cues. If you try to control a channel that is not in your partition, Eos will post an advisory that this channel is outside of the partition, and you must confirm that you want to control that channel. You will not, however, be able to store information for that channel.
When you record a target (cue, preset, palette), only those channels that are partitioned to you are recorded. Other programmers’ record actions to the same target can add to it (they do not replace it) unless channels are shared. When shared, the last value provided at the point of the record action will be stored.