Once the replica is created, it doesn't matter which one you specify as GDB1 or GDB2. The important part is what you specify as the sync direction which will determine where the data changes are going.
In your case, you edited E, and wanted to sync those changes to S. You filled the Sync tool out just fine - the sync direction was set to "Both_Directions" which means that any changes in E will get synced to S, and also any changes in S will get synced to E.
However - you aren't seeing the updates you expect.
Wondering if your edits are "outside" your replica extent. This could mean the spatial extent, if you had any filters on the layers.
Or perhaps you just need to call refresh on the version in your map doc (Add versioning toolbar, and use the Refresh Version on the workspace that you expect to see the changes in).