Solved! Go to Solution.
Honestly, it makes perfect sense if someone cares to read properly and tries to understand the workflow suggested. Instead of trying to use the unregister command from Command line tools (which are anyway deprecated), he is suggesting an alternate and safer way, to avoid any corruption of the Table.
1. suggesting you to export\create a copy of the concerned table in the same database
2. Delete the existing Table using ArcGIS Desktop\ArcObjects\ArcPy (this removes all dependencies, which was the initial concern)
3. Re-import the copy that you created in Step1 OR Recreate the required table from the copy that you made in Step1 OR Rename the copy that you created in Step1 (whatever suits you)
The original answer is just lacking a lot of detail and assumes the reader understands SQL. It's NOT a step-by-step. But it is something ESRI should document somewhere. Why isn't there a tool to unregister a table/feature from the geodatabase? Seems reasonable that if there a tool to register then there should be a way to unregister.