how to demote parts and and replace all the same components like sub-assembly created in inventor

[hien.leU5F2N]

I want to create a sub-assembly from components. I created it but i also want to replace all the components like the sub-assembly created without losing any constraints with the main assembly. I tried using Replace component, but all the constraints lost. Is any way to do this.
Thanks all 

[James_Willo]

You can only keep the constraints if the geometry is absolutely identical, and I don't just mean to look at, it needs the same internal IDs etc. So basically, if you want to replace a part and keep constraints, you need to get the part you're removing, create a model state inside, or do a save as/save copy as, this is the only way to get identical internal IDs so Inventor knows what to match. 

[CCarreiras]

Hi!

You mean, to do that repeatably (as in a model with different versions and keep moving between versions), or to use punctually?

Anyway... You can use Demote to create a new subassembly based in components already present in the main assembly. The constrains should maintain:

[hien.leU5F2N]

Sorry, may be my question is so confused to understanding. I mean I create a sub-assembly from 2 parts, and I already used the 2 parts in many places in main assembly. I demoted 2 parts to the sub-assembly and the others having the same 2 parts in main assembly still weren't demoted. I want those others to become the sub-assembly just created. I tried replaces those parts by the sub-assembly using Replace command, but it lost all constraints. But the main assembly have many parts must be replaced. Any way to do this quickly or I have to replace manually. 
Thanks all 

[CCarreiras]

Well, i think i understand.
When you do a "replace part" it will maintain the constrains if the part replaced is similar to the new part.

When the replaced part is somehow different from the new one, the constraints will disappear, because Inventor doesn't have the same conditions between those two parts. It's understandable.

But now, you're trying to replace a main assembly component (one part) for another component (the demoted sub-assembly with two parts), which is a very different case, between the replaced component and the new placed component, so it's normal that the constraints disappear.

Just one idea:

Try to first demote more two parts (like you did with the first case sub-assembly), and then replaced that second sub-assembly for the first sub-assembly you created (i'm guessing that these 2 demoted sub-assemblies are equal). They should have the same conditions. (Not sure if it will work, but theoretically, the conditions are maintained for both sub-assembly components).