From chicagoblackhawks.com: (link)
Game 4 of the Chicago Blackhawks’ Western Conference Quarterfinals series against the Calgary Flames on Wednesday, April 22 at 9:00 P.M. (CT) has been switched to WIND-AM (560) due to a conflict on the flagship station, News/Talk 720 WGN Radio. Veteran broadcasters John Wiedeman and Troy Murray will still handle the call of the Stanley Cup Playoffs contest, which takes place at the Pengrowth Saddledome.
The game will be joined in progress on News/Talk 720 WGN Radio at the completion of the Chicago Cubs matchup against the Cincinnati Reds.
Along with listening to the radio broadcast, Blackhawks fans can watch the game locally on Comcast SportsNet, with the call from Pat Foley and Eddie Olczyk, as regularly scheduled. The contest will also be seen across North America on VERSUS, TSN and RDS. Chicago currently leads the best-of-seven Western Conference Quarterfinals series over Calgary, 2-games-to-1.