You can copy, cut, and paste modifiers within an object’s stack, or into the stacks of other objects. Among other features, you can give modifiers explicit names to help you remember the intended effect.
The key to editing the stack is the Modifier Stack right-click menu, which this topic introduces.
To copy a modifier, do one of the following:
To create an instanced modifier, use Paste Instanced. To remove the instancing, click 
(Make Unique):
Rearranging and Sharing Modifiers
The easiest way to move a modifier to a different location in the stack is simply to drag it there. Alternatively, you can use the following cut/copy and paste procedure.
To share modifiers with other objects:
You can also drag from the modifier stack display to an object in a viewport.
Unique and Instanced Modifiers
By default, pasted modifiers are unique: they lose all connection with the modifier from which they were copied. Compare with an instanced modifier, which is shared between two or more objects. Changing a parameter on an instanced modifier automatically changes the same parameter on the other instanced objects.
Any instance of a modifier controls all other instances. Use this feature when you want a number of objects to take on the same feature.
For example, copying an instanced Bend modifier to a number of trees would make them all bend identically. Changing Bend parameters on any one tree would change the bend on all the others.
Using Make Unique with Multiple Items
Assume you have a group of trees all sharing the same instanced Bend modifier. If you select two of them and click Make Unique, a message asks, "Do you want to make the selected objects unique with respect to each other?"
You can use Collapse All or Collapse To to collapse all or part, respectively, of an object's stack to an editable object that preserves the cumulative effect of the collapsed modifiers on the base object. You might choose to do this in these cases:
After you collapse an object’s stack, you can no longer parametrically adjust either its creation parameters or the individual modifiers affected by the collapse. Animation tracks that were assigned to such parameters also disappear.
Collapsing the stack does not affect the object’s transforms; it affects world-space bindings only if you use Collapse To. Collapsing the stack does not save memory if the stack contains no modifiers.
Save Save Selected to preserve a copy of the original parametric object.
Collapses the stack, up to and including the chosen modifier, into an editable object. Modifiers on the stack above the chosen modifier are not affected, and you can still adjust them individually.
The resultant object type depends on the uppermost modifier that outputs a specific geometry type, if any. If the stack contains no such modifier, the result is an editable mesh. If the collapsed portion of the stack contains a modifier that outputs a specific geometry type, and no other such modifier is above it, the result is that type of object. For example, if the topmost such collapsed modifier is Edit Poly, the resultant object is Editable Poly.
Collapses the entire stack into an editable object, other than world-space bindings. Any world-space bindings on the stack are left intact.
The resulting stack list shows a single entry: Editable Mesh, unless any modifiers on the stack output a different type of geometry. For example, if the topmost such modifier is Edit Poly, the resultant object is Editable Poly.
If no modifiers are applied to the object, choose one of the Convert To options:
