What is the act that can serve as an expiation for someone who sells alcohol out of necessity due to special and limited circumstances?

"Necessities permit the forbidden" is a well-established principle supported by Islamic texts. The necessity that allows committing something forbidden is when a person is in a state where they face destruction or are on the verge of destruction because of it, such as eating a carcass when starving. One must fear Allah and seek alternatives. If this act is committed without necessity, then one must repent, and there is no specific expiation for this sin.