how to remove the root node without the children affec

Hi

I am initializing an XML in the memoryDOM. In this process I want to remove
the outer node only. But removing that should not removed the sub nodes

<remove-node>
    <not-remove>
            <sub nodes></sub nodes>
    </not-remove>
</remove-node>

After the removal...I need to get it as

    <not-remove>
            <sub nodes></sub nodes>
    </not-remove>

how is this possible..Please help

Anish