A Manhattan appellate court Thursday revived claims against Winston & Strawn by a former rainmaking partner who alleged the law firm subjected him to “decompression,” a firm policy sharply reducing his pay after age 65, in violation of a special compensation agreement.

Anthony F. LoFrisco, a partner in the New York office of the Chicago-based firm, had long been one of the highest-paid lawyers at Winston & Strawn, owing to his close client relationships with corporate chieftains, particularly former General Electric Co. Chairman Jack Welch. In a 1994 arrangement, Winston & Strawn agreed to pay LoFrisco compensation equal to at least 13 percent of its GE billings.