RE: HDD passwork reset or removal Dell Latitude E7450
You will need to call Dell support. There are two issues: first, the CMOS portion of the password must be removed (that requires ownership verification during a voice call to Dell support).
That will not, however remove the password from the drive. Once it's done, if you don't need the data on the drive, the cheapest option is to replace the drive. Anything else will cost you a trip to a data recovery service to have the password removed from the drive -- it's not user-accessible once set; it requires a set of specialist tools. That's why it's critical to record the password in a safe place once it's been set.