until it was sued in January 1987 but it does not refute Sonoco's claim that American's attorneys contacted Sonoco by April 30, 1986 with regard to Sonoco's pending lawsuit against Thunderbird.  At first American's attorneys would not identify their client and Sonoco sent copies of its motion for summary judgment and brief to American's attorneys.  By contacting Sonoco in the midst of Sonoco's suit against Thunderbird, American demonstrated that it was fully aware of its potential liability some time prior to April 30, 1986.  How much earlier we do not know, but we are concerned that American now hides behind an argument that notice was not timely when American obviously received notice sooner than it admits and, through its own efforts, prevented Sonoco from providingexcusable.  Sonoco notified Thunderbird when the panels failed to arrive at the Missouri construction site and demanded in writing that Thunderbird compensate Sonoco for the loss.  Sonoco pursued its claim against Thunderbird and notified American of its claim when it discovered that American insured Thunderbird--approximately twenty-one months after the panels were lost.  American knew of its potential liability when it contacted Sonoco during the lawsuit pending against Thunderbird.  Sonoco's lack of knowledge regarding American's identity and its diligence once it learned American's identity, coupled with American's own reluctance to admit when it received actual notice, provide an excuse for the delay in notice.  See Charter Oak Fire Ins. Co. v. Snyder, 22 Ill.App.3d 350, 356, 317 N.E.2d 307, 311 (1974) (lack of knowledge