How to Separate 3d objects which are already union by union Command in AutoCAD?

As Mr. Shakeel answer , There is an option called Separate which it uses for separating an union objects or you can use  Explode  option with recommended to use the first option .

The SOLIDEDIT command (open the Edit Solids toolbar for easy access) has an option that lets you separate solids. Many people have been confused about this option, because it requires that the solids be non-touching. So aren’t they already separate? It turns out that the UNION command can combine non-touching solids. Think of it as a way of grouping solids. Then, the Separate option can separate these solids.

Thank you mr. Shakeel for the correct answer but also the addition of mr. Alomer!

Thanks for invitation.

with Mr.: Muhammad Shakeel answer.

Also I agree with Mr. Shakeel answer ...thank you Mr.Syed Shan Haider