Actually, two methods are available for you to format your HD.
Firstly, open cmd as administration. Then type the following commands in order and press Enter after typing each command.
select disk x
x is the disk number that you noted for the encrypted drive from the section above. Finally, the BitLocker encrypted drive is formatted and all the data including BitLocker encryption is cleaned up.
- Method 2: Disk Management
Firstly, open Disk Management window. Then right-click the drive encrypted with Windows BitLocker and select Format option. This method is aimed to format a volume rather than a hard drive.
Finally, this article is worthy of reference.
Hope it help!!:):):):):)
How to Format Bitlocker Encrypted Drive without Password or Recovery Key