How to clear a known password in AMI BIOS?

I have just got a tiny no-brand MicroPC and foolishly set an Administrator password in its AMI BIOS. I DO KNOW the password, but still want to get rid of it. Typically, when one wants to clear a BIOS password it is enough to just change it to blank, but not in this BIOS. If I just press enter for a new password when changing it, I get a message “Invalid Password”. I can change it to anything else, but not clear. BIOS does not have a dedicated option to clear the password either. Is there some trick to it?