How do I delete user without access to other accounts.

I have 3 accounts on my mac and only have the password to one. I need to delete that account but I can't log into the other 2. I would really appreciate and suggestions.

If the only account you have a password to is an Admin account do this:

Log on to that account and create another Admin account and make sure you save the password for it. Sign off and then sign on to the new Admin account you created and you should be able to remove the accounts you no longer need. Be aware that you may lose data so it's a good idea to have a backup before you attempt to do anything.

Assuming the account you do have a password for is an admin account.... open System Preferences » Users & Groups. Click the lock at the bottom and authorize it. Go to the user accounts that you don't have passwords for and reset them.

If none of those other 2 are admin accounts, then you either will need to make a new admin account as chscag recommended, or give one of those 2 existing accounts admin privileges via the option on the same screen you reset the passwords from.