Change the base unit of measure（更改度量单位）
根据SAP的提示信息，更改度量单位需要满足：1、该物料没有当期和前期库存；2、不存在该物料的采购申请、采购订单、计划协议。然而事实上远没有这么简单。
根据SAP Note: 138767，更改物料度量单位时，系统会进行以下检测：
The base unit must not be defined as an alternative unit of measure for the material
No International Article Number must be assigned to the base unit
No proportion/product units must be defined for the material
No configurable material must be assigned
The material must not be used as a configurable material
Stock must neither exist for the previous period nor for the current period
No physical inventory must be active
No reservations or dependent requirements must exist for which the deletion indicator is not set
No planned orders must exist
No purchase requisitions, purchase orders or scheduling agreements must exist for which the deletion indicator is not set
No WM transfer requirements, no WM quants or no WM posting change notices must exist
The material must not be a bill of material
The material must not be contained in a bill of material
The material must not be used as a production resource/tool
The material must not be used in task lists
No standard cost estimate must exist for the current or future period
No production orders must exist
No planned independent requirements must exist
No run schedule headers must exist
If the base unit has dimensions, no serial number profile must be assigned
No sales and distribution documents must exist which have status Not processed or Partially processed.
如果存在前期库存，根据SAP Note: 30656的提示，需：
- Post the same amount to current period stock (for example, using movement type 561) so that previous period stock and current period stock are identical.
- Make a withdrawal posting in the previous period for the stock together with posting date (for example, using movement type 562).
这是 SAPFans 给的一个详细步骤（带批次管理）：
- wait until last day of the period
- post GI using 201 (but I not sure why SAP says used 561)
- period close and open new period
- uncheck the Batch Management indicator in material
- reverse the GI with 202
- delete and archive
