PO gets Self Approved in Correction Mode

Hi All,

     Business user creates a PO and approves it which goes as per approval hierarchy and gets final approved. But in those cases where there is correction in PO after approval as user resubmits for reapproval it get auto approved by him without getting forwarded to the next hiearchy.

     Please let me know why this issue is existing in revision cases.

Thanks,

Bhupati