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The amend option should be used when the purchase order has already been send to the vendor. Click on 
to amend a particular purchase order. More information regarding amended POs is available under MORE INFORMATION.
Edit Purchase Order
New Purchase Orders from an open posting period may be modified. Only fields that are allowed to be edited will be displayed.
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Individual user purchase order processing is controlled by a variety of variables, such as User account where the Account Filter and Role (and the Permissions assigned to those Roles) are defined for each user, User Preferences, Rules, etc.
When using the Amend option on a Purchase order, you are not permitted to change the Vendor if the PO has already been invoiced. You will also not be permitted to modify an existing item if that item has been invoiced..
By default the system will give a warning if the budget's remaining balance will go negative. Remaining balance is either unencumbered balance or unencumbered balance - outstanding requisitions depending on whether the pre-encumbrance module is installed (see Admin/Modules) and on the specific rule(s) the district has enabled. However, this can be customized to suit the needs of the district (see rules org.ssdt_ohio.usas.model.po.DefaultBalanceCheckWarning and org.ssdt_ohio.usas.module.preencumbrance.POBalanceCheckWarningExcludePreencumbrances).
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