Withholding Tax Changeover 
Purpose
In your company, you have been using an SAP standard version of classic withholding tax. After upgrading to Release 4.0 or higher, you can use extended withholding tax instead of classic withholding tax.
For more information about the functions of classic and extended withholding tax, see Withholding Tax
In order to change over to extended withholding tax, you cannot just simply activate extended withholding tax; in this case, you would not be able to carry out further processing to items already posted in the system. All relevant Customizing, master, and transaction data must be converted so that it can then be used in extended withholding tax.
SAP provides a tool that supports the withholding tax changeover by automatically converting the relevant withholding tax data. The individual steps of the withholding tax changeover are listed below. To access the tool for converting withholding tax data in the IMG, choose
Financial Accounting
under
Financial Accounting Global Settings 
Withholding Tax Withholding Tax Changeover 
.
Recommendation
The individual steps of the withholding tax changeover must be carried out in the order specified.
Prerequisites
Caution
First carry out the withholding tax data conversion in a test system.
Once you have converted the withholding tax data and activated the extended withholding tax function, the data conversion cannot be reversed.
Caution
Activate the extended withholding tax function for the company codes for the changeover only when explicitly directed to do so.
Upgrade to Release 4.0 and Above
It is essential that you complete all tasks relating to the release upgrade before starting the withholding tax changeover.
System Block
You must ensure that no documents are posted in the company codes concerned during the withholding tax changeover.
Recommendation
Block your system for all end users and carry out the conversion runs at the weekend.
Logistics Invoice Verification
If you do not use invoice verification in your organization, you do not need to take any action at this stage.
The extended withholding tax function is only supported by the Logistics invoice verification; it is not supported by the conventional invoice verification. You can therefore no longer use the conventional invoice verification once you have carried out the withholding tax changeover.
Recommendation
Change over to the Logistics invoice verification before converting the withholding tax data and changing over to extended withholding tax.
Note that the range of functions provided by the Logistics invoice verification has been extended with each release since Release 4.0B.
For more information about the combination of extended withholding tax and invoice verification, see notes 133426 and 133435.
For more information about replacing the conventional invoice verification and about the features of the Logistics invoice verification, see notes 127366 (for Release 4.0B), 116272 (for Release 4.5B), and 144081 (for Release 4.6).
Activities
In the Implementation Guide for Materials Management , choose
Invoice Verification Logistics Invoice Verification.
Make all the required system settings for the Logistics invoice verification.
Process Flow
The changeover process is made up of the following procedures:
Preparations
Converting Data and Activating Extended Withholding Tax
Converting the Withholding Tax Data and Activating Extended Withholding Tax