disabling known master password in OS 10.3.9

I set a master password on my imac using OS 10.3.9. I know the password
and am able to get into my system. It's just that I no longer NEED
that feature and would like to undo this action.

I can change the
password to a new one, but so far cannot disable it altogether. I even
tried leaving blanks for the "new Password" but then it insists I set a
new one.

Any way to be rid of this? Thanks for any info.

bill