Basically, if some one deletes the device in Intune accidentally when it's powered off. When the device is powered back on, it still will check in with Intune, and then remove the policies and company data. Please just click Delete devices from the Intune portal for more details.
In addition, the end user also can unenroll the Intune managed device. It can be performed from the Company Portal. Please refer to the following guide for more details.
Unenroll your Android device from management
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