All sites in Myplace take part in a systematic rollover process ahead of the start of the academic year. 

This takes place in June preceding the start of the year.  A full description of the rollover can be found at Rollover Explained.

Some classes may have a "None" rollover action, meaning that absolutely no action  will be performed during the rollover processes.

Sometimes however it is desirable "rollover" a site at a later date

Turnitin

When a site is rolled over a new Turnitin class is created, along with new Turnitin Activities. This means that the submissions for the forthcoming academic year do not conflict with the previous year's submissions.

Where a site does not rollover (move and none rollovers) this does not happen, and the forthcoming year's submissions are added to the existing Turnitin class & activity.

For "move" sites this is normally the desired behaviour: there is only ever a single site available.