Re_activate Historical Version of PO

Hi,

SRM 5.0 ECS.

I want to re-activate the historical version of PO, below is the details what happened

1) Limit PO created with Internal Order as account assignment

2) Confirmation and Invoice document created

3) Internal order changed to cost centre in the PO,as limit PO allowed to change account assignment

4)PO gone in to error (backend application error) as this functionality is restricted in the Back-end

5) The same functionality resticted in the SRM also now (Limit PO should not allow to change account assignment)

6) To correct error PO i need to bring back this PO in to original position (i.e step 1above)

7) My requirement is to activate first historical version of the PO (i.e Re-activation of Historical version)

Is there any way to activate historical version of PO

Regds,

Jai