Update: The GSN Online Schedule confirmes the below changes for 4/21.
From many posts here and on the Verizon Fios and DirecTV schedules (though not Zap2It or TVGuide online), the following weekday schedule changes are rumored to occur starting Monday, April 21st:
*At 9am, Password Plus (Ludden) will replace Blockbusters
*At 9:30am, Whammy! (GSN) will replace Press Your Luck
*At 10am, The $25,000 Pyramid will replace Sale of the Century
*At 10:30am, Sale of the Century will replace The $25,000 Pyramid
*At 11:30am, Lingo (Woolery) will replace The $100,000 Pyramid
*At 2:30pm, Chain Reaction (GSN) will replace The Pyramid (GSN)
The following changes are rumored to occur on Saturday, April 26th and Sunday, April 27th:
*At 9am, Blockbusters will replace Password Plus.
*At 9:30am, Press Your Luck (80's) will replace Whammy!
All Times Eastern
The GSN Online Schedule is only seven days in advance, therefore the April 21st schedule is not available yet. There have been no new "advanced pdf schedules" released yet.