How to change Android system boot slot form A to B

fastboot set_active command does not exist fastboot change slot Execute magiskboot repack to repack the boot image, and you will get a file, flash this file to device by fastboot INFO Official fastboot change slot 8GB MEMORY Built-in Wifi Built-in Camera with NumPad Flat Keyboard VGA SLOT HDMI SLOT SD CARD SLOT DVD DRIVE USBLAN PORT

fastboot_ error_ failed to identify current slot But I want without fastboot command My usecase is the bootloader need to check the currect active slot and set the proper suffix How can I