Requisition Workflow

SCM needs a requisition framework where the field can request materials as well as purchasing being able to send out a requisition to a supplier and then be able to convert that requisition into a PO with all or any number of the items on the requisition. There also needs to be an approval workflow option to approve the requisition before it goes to a supplier. Lastly, be able to revise the requisition and re-send if the need arises.