Here we would like to draw your attention to OS71 transaction code in SAP. As we know it is being used in the SAP CA-GTF (General Application Functions in CA) component which is coming under CA module (Cross Application).OS71 is a transaction code used for ECH: Change Number Format in SAP.
It comes under the package CC0C.
Transaction OS71 technical data table
|Purpose||ECH: Change Number Format|