BP Update in CRM to Flow to ECC

Hi Experts,

I have come across a scenario where ECC is the leading system and the Customers created in ECC are flowing to CRM using the Customer_Main Adapter Object. The Adapter Object BUPA_MAIN has also been run in R3AS but the Destination is pointing to GroupWare System.

Now the ask is to change the customer details in CRM and the same should update in ECC system. How can I achieve this? Any suggestions on this.

I have already created "All Business Partner" Subscription for the R/3 Site. So now when I change anything in CRM, in SMW01 i can see BUPA_MAIN BDoc type sending it to 2 Sites- one to GroupWare and other TO R/3 site. But the R/3 has error as "The ASSERT condition was violated".

Can anyone help me in this scenario?

Thanks

Niket