SQL Server 2012 :: How To Copy Nested Sub-tree From One Node To Another

I have a tree and I need to copy a nested sub-tree (an element with its children, which in turn may have their owns) from one place to another.

The system should allow to handle up to 8 levels. I do know how to move, but cannot figure out how to copy.

Below is a working example With Create Table, Select and Cut / Paste (implemented via Update).

I would like to know how to copy a nested tree with reference id 4451 from Parent_Id 1 to Parent_Id = 2

--***** Table Definition With Insert Into to provide some basic data ****

IF (OBJECT_ID ('myRefTable', 'U') IS NOT NULL)
DROP TABLE myRefTable;
GO
CREATE TABLE myRefTable
(
Reference_Id INT DEFAULT 0 NOT NULL CONSTRAINT myRefTable_PK PRIMARY KEY,

[Code] ....

How to Copy nested sub-tree 4451 with all its children to Parent_Id 2, without deleting from Parent_Id = 1 ?