Here are the steps to copy entire data flow in BW 7.3.
1) Right click on the cube and select copy data flow.
2) Then select Downwards.
3) The copy data flow wizard will start. Click continue.
4) Choos the source system. In this case it was original/same. Click continue.
5) Then either create a new data source or use original. Here i have created a new one.
6) Create new cube, DSO and click continue.
7) In next step, system will create new transformations. Click continue.
8) In next step, system will create DTP’s. Click continue and then click Finish.
9) After that, you will see the logs while the new data flow is getting created.
10) See below that the new data flow has been created.