OOooh! Passwords are pretty much set in stone unless you're a hacker

But, here's something you could try and maybe more help is on the way from
other folks:
If you can get into the file, then you'll need to copy everything you can
and re-create it in a new file and save it without or with a new password.
To protect yourself in the future, you could create a duplicate worksheet
with another password being an answer to a security question or other
password for the original authorized users to gain access to this copy.
Again, you won't have access to the original file and will need to create
another copy of this copy and re-name this copy and change the password.
The 'forgot password' feature is a good addition and may have been added to
Office03? Let me know if this answer is not clear or you need more help.