How to change Android system boot slot form A to B

Checking Android's Currently Active Partition Slot fastboot get active slot So i decided to flash twrp into a boot slot via fastboot then, i set the active-slot to that but then I still don't get twrp idk why Now, I can get into fastboot get active slot On AB devices, flashed slot is set as active Secondary images may be flashed to inactive slot flash PARTITION Flash given partition, using the

fastboot set active slot Display a bootloader variable fastboot set_active suffix: Sets the active slot If slots are not supported, this does nothing fastboot boot