1 Connect trackpad
2 Go to Bluetooth System Preference and right click on trackpad, don't click anything else yet. Leave it open
3 Turn off trackpad
4 Select "Rename" in the still open right click menu
5 Rename the trackpad and click "Rename" (or press Return key) the pop up
6 Turn device back on and connect. You may need to pair it again by connecting it to the computer with a USB to Lightning cable.
If you don't have an extra mouse or trackpad to do step 3, you can press the Option key five times to use Mouse Keys
Control the pointer using Mouse Keys on Mac - Apple Support