Configure replica mapping if, on the host in the DR site, you have ready-to-use copies of the source VMs. These can be restored VMs or replicas created by other replication jobs. Veeam Backup & Replication will synchronize the state of these ready-to-use VMs with the latest state of the source VMs and will use these VMs as replicas. You can also use replica mapping if you need to reconfigure or recreate replication jobs, for example, split one replication job into several jobs.
https://helpcenter.veeam.com/docs/backup/vsphere/replica_seeding.html?zoom_highlight=replica
+mapping&ver=120