Time Machine. Password forgotten. How to erase it

I have My Passport for Mac and I did a backup copy with Time Machine. Now, it seems that I forgot my password because Time Machine does not accept the one I type. I know the password can not be restored. Then, what I need is to know how can I erase or format my WD in order that I can process another backup copy. I want to avoid to buy a new one. I tried to look for an answer in FAQ but the one I found is not valid because it is based in old versions of Mac OS.
Thank you in advance


You may type an incorrect password 5 times and the software will ask you if you want to format the drive.

You can also just go to disk management and format the drive. This will delete the password but will also delete all data stored in the drive.