How to override public virtual bool Approve(SourceAssign source) Method

I need to override a piece of Acumatica’s Approval process that prevents from Apprving a Rejected document. Not sure why Acumatica has put this control in place but it happens many times for us that a documents gets rejected to add some supporting documents and when documentation completed, then this document can be approved. The piece of the code that prevents from approving a rejected document is in EP\Descriptor\Attributes.cs as follows:

        public virtual bool Approve(SourceAssign source)
        {
            EPApproval item = (EPApproval)this._Rejected.SelectSingle(GetSourceNoteID(source));

            if (item != null)
                throw new PXException(Messages.CannotApproveRejectedItem);

            if (UpdateApproval(source, EPApprovalStatus.Approved))
            {
                RegisterActivity(source, PO.Messages.Approved);

                return true;
            }

            return false;
        }