How to increase standard field size in table by create new EDT

Hi all,

I need to increase Table : VendInvoiceInfoTable , Field : Num size 20 to 50 and create new EDT size string 50.

Now change EDT filed Num (extension table :VendInvoiceInfoTable ) I getting error like below

Error Path: [AxTableExtension/VendInvoiceInfoTable.Customizations/Fields/Num/ExtendedDataType]:The extended data type 'NewEDI' is not derived from 'Num'. Project_Customize (VAR) [Customizations] K:\AosService\PackagesLocalDirectory\Customizations\Customizations\AxTableExtension\VendInvoiceInfoTable.Customizations.xml

I'm not sure, I can add new EDT standard filed or not ?

Any suggestions to resolve.

Thanks your advance.