"Stock Fold" feature is not available in Part Navigator.
It is not possible to change "Stock Fold" value.
How to modify an existing "Stock Fold"?
Solution To edit an existing stock fold, Please execute the following
Right click on the spline path segment that belongs to the stock fold and click on "Spline Path"
This will launch 'Stock Fold' dialog (not 'Spline Path' dialog as usual)
Make the necessary changes in the active fields of 'Stock Fold' dialog and click OK
Hardware/Software Configuration Platform: INTL64
OS Version: 764