Working closely with Bruce and Cooper, Wilson presented a ceasefire offer to Kosygin on 11 February 1967 on behalf of the United States, which Kosygin promised would be passed on to Ho. A few hours later, Cooper left his hotel to attend a performance of "Fiddler on the Roof" while informing the hotel staff that he would be at the theater if any phone calls came in for him. Cooper was at the theater when he an usherette told him that there was an urgent call from Washington, saying that a Mr. Rostow wanted to speak with him at once. In his telephone call, Rostow attacked Cooper for the conciliatory tone of Wilson's letter, which he called appeasement, and demanding it be rewritten to make it much tougher, a gesture that Cooper felt was meant to sabotage Operation Sunflower. As demanded by Rostow, a new letter with considerably more confrontational tone was given to Kosygin, which led him to accuse the British and Americans of negotiating in bad faith.