URL    = "https://b24-ar17wx.bitrix24.by/rest/1/1o2...";
    ChatID = "578";

    Title = "New chat title";

    Result = OPI_Bitrix24.ChangeChatTitle(URL, ChatID, Title);

    URL    = "b24-ar17wx.bitrix24.by";
    Token  = "ec4dc366006e9f06006b12e400000001000...";
    ChatID = "580";

    Title = "Another title";

    Result = OPI_Bitrix24.ChangeChatTitle(URL, ChatID, Title, Token);