Change SourceSystem for a single DataSource

Hi all,

In my Development system there are few datasources mapping ECC Production system instead of Development system. When I want to check or modify those transfer rules, it gives me an error as it's not possible to connect BW-Dev to ECC-Prod and I cannot reactivate or modify anything.

As ECC-Dev and ECC-Prod systems already exists in BW-Dev, I don't know how to do to change the source system of those DataSources withoug creating new DataSources and affecting anything.

I've read about changing datasources but it looks like it's only possible when all datasources have to change source system, for example when there's a new ECC system to which BW must be mapped, and I've also read that changing Source System for a single DataSource is not possible, is that true?

Any idea?

Thanks.