Actually, this is pretty simple. Buy a 25k CTS pot. Gently bend back the four tabs of the cover on both pots. (Red arrows.) Swap wafers, and reassemble both. The 25k becomes a spare pot of whatever value your S-1 was, and your S-1 becomes 25k.
You don't need to disassemble the actual switch part as I did. I did that because I'm doing a more extensive experiment.
(Converting it to 6PDT to parallel three Red Devils with one switch.)