In order to change the name of the volume collection, the "replicate to" field of each schedule must first be set to "none".
After you edit the volume collection, you can set the replicate to field back to the replication partner.
The volumes do not need to be re-seeded on the downstream array because they are already there. However, the snapshots belonging to the old volume collection name will be orphaned. This means that they will need to be manually removed from the downstream array as time progresses since they no longer fall under the current retention schedule.
You will be able to locate these snapshots under the individual volumes. The new volume collection will only show the newly replicated snapshots.
You can change the volume collection name and schedule without any issues, no need for reseeding.
However all the snapshots prior to the name change will become orphans / un-managed and need to be manually deleted.
Infosight > Wellness tab will list all the affected volumes, if there is a lot of them you can script the deletion.