The biggest change coming to the Norway Pavilion is a Frozen-themed ride, which would replace the aging "Maelstrom" ride, which explores Norway's history and culture. According to a Norwegian news report, the Maelstrom ride could shut down as soon as October to make way for construction on the new Frozen ride.
However, it seems Disney may have plans for a more extensive Frozen overhaul of the entire Norway Pavilion. The Norwegian news report (you can watch the video here, but be sure to turn on English subtitles) claims Disney is looking to convert the Norway Pavilion to be focused almost exclusively on Frozen.
Besides cashing in on the massive success of the film, it seems Disney wants a financil investment from the Norwegian government to help refurbish the pavilion in order to keep the focus on the country -- and not Frozen. (Several Norwegian companies and the Norwegian government originally helped fund the creation of the Norway Pavilion at Epcot as a way to promote tourism. Norway contributed $200,000 annually from 1992-2002 to help maintain the pavilion.)
According to the Norwegian news report, Disney is starting to make plans for additional changes to the Norway Pavilion, beyond remaking the "Maelstrom" ride. Plans include eliminating most of the shops in the Norway Pavilion to make room for a Frozen meet-and-greet, and other Frozen-related activities.