Hi Narinder,
For every user created on a HANA system, a schema is created with that of the user name. Data can be loaded in to this Schema through different Data Provisioning techniques. These tables might have been loaded through Data Services or SLT (Here you have loading and replication).
Each of these tables in these different scehmas are separate instances and a table in ECC can be loaded in to different schemas under the same name but have to be in different schema. If trying to load in to the same schema the records will be appended or the table can be overwritten.
Different users are using the same server that you are using and each one is loading or replicating these tables for their own practice purposes.