Put a capacitor in series with a piezo tweeter to attenuate it. That's all there is to it. As far as the value, I'm not familiar with the 1197, so I can't say for sure. But the KSN 1038 is attenuated a little more than 6dB using a 0.1uF capacitor.Here's a chart:
1.0uF -1dB
0.47uF -2dB
0.33uF -3dB
0.22uF -4dB
0.1uF -7dB
Your tweeter may have different electro-mechanical parameters, and would need different values of capacitors for the same attenuation. You might want to check and find out.