A cache memory stores a cache line associated with a coherence state field set to a first modified coherence state. The cache memory implements a default first coherence state update policy in which the cache memory is biased to retain write authority for the cache line. Responsive to a store request, the cache memory updates data of the cache line. If the store request indicates a change from the default first coherence state update policy, the cache memory updates the coherence state field from the first modified coherence state to a second modified coherence state in which the cache memory is biased to transfer write authority for the cache line. If the store request does not indicate a change from the default first coherence state policy, the cache memory refrains from updating the coherence state field from the first modified coherence state.