Purchase Orders

Reasons for use of Purchase Orders

A purchase order is a legally binding document between a supplier and a buyer. It details the items the buyer agrees to purchase at a certain price point. It also outlines the delivery date and terms of payment for the buyer.

There are several reasons for use of Purchase Orders:

  • To control the acquisition of goods and services when price is a primary consideration. An effective purchase order can move the purchase process forward from discussion to commitment by laying out products, prices, timelines and other critical terms and conditions.
  • The contractual nature of a purchase order protects both the buyer and the supplier in case of a dispute about the nature of the order; a great PO leaves no questions unanswered.
  • To create an "encumbrance" in the general ledger of accounts helping you manage your budget.
  • By using a Purchase Order, everyone involved in the purchase cycle can track the order by referring to the same number.
  • Utilization of a Purchase Order protects WHOI and includes WHOI’s Terms and Conditions.

When to Use Purchase Orders

The Institution requires that it’s community utilize a Purchase Order for

  • All Procurements with a dollar value of $5,000 or greater.
  • Independent Contractors (as defigned here Independent Contractors)

How to Generate a Purchase Order

To generate a Purchase Order, complete a Purchase Requisition Form and forward it (along with supporting documentation) to the Procurement Department (MS#1).

Alternately, electronic scans can be sent to

The Procurement Department will utilize the information to generate a Purchase Order.  Procurement will send the order to the supplier.

How To Identify the Supporting Documentation Needed for Purchase Orders

When ordering “Off the Shelf” items we need.

  • Purchase Requisition
  • Quote or Pricing
  • If > $9,999.99 (evidence of price comparison in the form of three quotes, with the lowest quoted price selected)


  • If > $9,999.99 Sole Source / Urgent Purchase Justification Form

When ordering any Custom Part (something that’s made specifically for us) or Service we will also need.

  • SOW (Statement of Work)

How To Track Purchase Orders

To review or search for an existing or past Purchase Order, you can use the PO Query.  This is an online application that allows you to search for vendors, stockroom inventory, vouchers and existing purchase orders.
» View step by step guide for using PO Query (ppt)


How To Complete A Change Order for an Existing Purchase Order

Procurement issues Change Orders to modify existing Purchase Orders (POs) with concurrence of the user department. This type of order changes a PO and notifies Accounting Services and the vendor of the change. If the Change Order results in a dollar amount change to the PO, your encumbrance will be adjusted in the financial systems and the change will be viewable in your FSR.

Change Orders are issued:

  1. To add or delete an item or items on a Purchase Order.
  2. To change the ending dates on a blanket order.
  3. To change the description of an item(s).
  4. To change price(s) and/or item(s) if the order total changes by $100 or more.
  5. Per vendor request with consultation of the user department.
  6. To change an order to/from positive approval (to approve invoices prior to payment).

Change Orders should be issued

  • to modify encumbrances for budgeting purposes
  • to modify funding strings or account codes on an order

A Purchase Requisition Form must be processed to create a change to a Purchase Order. Please include the Purchase Order number in the text of any Purchase Order change you might request. Please also indicate "Change Order" in the note at the bottom of the form

Authorizations needed for a Purchase Order are also required on a Purchase Order Change 

If  the change increases the value of the Purchase Order beyond the authorization limits of the original approver, the change must be approved at the next approval level.

Note only those items you wish to change when processing a Purchase Order Change. Any information not noted as needing change will be left as is.

Please include the text “CHANGE ORDER” on your requisition along with the original PO (and/or requisition) number.

 At the top of this page look for "Related Files" for a change order guide.

Change orders should be sent electronically to


How To Cancel, Close, or Disencumber Purchase Orders

From time to time, it may be necessary to cancel a Purchase Order. You may have determined the items or services were not needed or could be better provided from another source, the supplier may not be able to provide all the items you have requested or the final payment for the items or services were less than expected and you wish to eliminate an encumbrance.

To cancel a Purchase Order, please process a Purchase Requisition Form noting the reason you wish to cancel the Purchase Order and the Purchase Order number of the order you wish to eliminate. Budgetary authorization must be secured on a request to cancel a Purchase Order.

Requests to cancel, close or disencumber should be sent electronically to

Last updated: August 12, 2016