The boards of Ashland Community Hospital and the San Francisco-based Dignity Health group have approved a merger of the two organizations. The ACH board also voted Wednesday to formally ask the Ashland City Council to approve the partnership and a lease agreement with Dignity Health, said Janet Troy, ACH director of development. The alliance requires the city's approval because when the city turned the hospital over to the not-for-profit Ashland Community Healthcare Services in 1996, it retained sole corporate membership, according to city documents. Dignity Health and ACH boards voted to approve the agreement on Tuesday and Wednesday, respectively, according to an email from ACH board Chairman Doug Gentry.