If the two who want nothing "disclaimed" the inheritance so that even though they normally *should* or would have inherited, they did not, then only the two who actually did inherit must sign the listing. (People cannot be forced to inherit against their will, so heirs can say "no thank you" and never receive the asset or property.) If the estate has not closed or probated yet, if any do not want to inherit, they can contact the probate or surrogate's court for instructions on how to disclaim their inheritance.If all four did in fact already inherit and are owners of the property (e.g. are on the title), then they all need to sign the listing agreement, unless  the two who don't want anything from the home first quit claim it to the other two.