Possibility #1 is to refer to the HOA bylaws to see what it says about calling a special meeting of the board. Probably takes more than one member. Next possibility is to wait for the next regular meeting, carefully observing what may be necessary to be sure your request is on the agenda. An overriding problem remains, however: if the board does take up the matter at a regular or special meeting, how likely is it simply to say "no"? If the lien is legit, a principled board would, perhaps, be right in refusing to negotiate.
