Hello EhsanSikdarBD,
There is no option to reset an SC5020 through DSM. Refer to page 301 of the Dell Storage Manager 2016 R3 Administrator’s Guide: https://topics-
cdn.dell.com/pdf/storage-sc2000_administrator-guide_en-us.pdf

Reset a Controller to Factory Default
Reset a controller to apply the factory default settings, erase all data stored on the controller, and erase all data on the drives.
Prerequisites
The Storage Center must be an SCv2000 or SCv3000 series controllers.
The controller must be running Storage Center version 6.7 or later.

You will need to contact support to get assistance with this.