Change pointers (better to say ALE change pointers) are essential within ALE (Application Link Enabling) technology. While there is any change (think of CRUD type of operation) done to data (like biz object in SAP e.g. material, customer, sales order etc.) a change documents are generated. In case change pointers are setup for the biz object the changed data is transferred to other systems.
To enable the data exchange like this the change pointers, need to be activated in the system. For this there is a t-code BD61 (program RBDTBDA1) available. It sets flag X into field ACTIVE of table TBDA1.