Q: With board approval, I bought a studio in a Manhattan co-op in 2002 as a pied-à-terre. Several years ago a new board imposed a rule that studio apartments can no longer be used as pieds-à-terre. A broker told me the policy had reduced the market value of my studio. Can the board impose such a policy?

A: New York State has given co-op boards the right to withhold consent to a sale “for any reason or for no reason” provided it does not violate federal, state or local antidiscrimination laws, said Lior Aldad, a Manhattan co-op and condominium lawyer. A board can change its policies at any time, and shareholders who bought under a former policy will have no claim against the board. Mr. Aldad noted that since the writer bought her apartment as a pied-à-terre with the board’s approval, she can continue to use it as such. But any sale of the apartment must be approved by the board, which will then impose the new policy.