How would I remove my ex-wife as sole survivor to my State of Wisconsin pension?

One would need to review your divorce decree, settlement agreement and QDRO for your pension to determine if your ex has "survivor rights" to your pension. If so, you would be in violation of the court orders to have her removed. If on the other hand, you were awarded your pension as part of your property division and she has no rights to it, you should be able to complete paper work provided by the state to remove your ex spouse as the surviving beneficiary should you die.