Three of the changes are in the backs where Lori Josephson starts at scrum half in place of Chelsea Guthrie and Lisa Gauthier and Katie McNally take over on the wing from Natasha Smith and Brittany Waters.
In the forward pack, Cindy Nelles replaces Jacey Murphy at No. 8 for the game.
"We want to have more options for the future and this is the time for us to try these options as our next campaign will be only next year," Ratier said in a statement Tuesday. "We want to see them starting a game in key positions."
Tiffany Picketts, Camille Provencal-Aube and Gillian Allen could make their national team debut after being named to the bench.
Canada was beaten 40-22 by the New Zealand Black Ferns on the first day of tournament play in Calgary while the Americans lost 39-13 to reigning World Cup champion England.
England plays New Zealand in the other game Wednesday.
The tournament wraps up Sunday in Edmonton when New Zealand plays the U.S. and Canada faces England in a rematch of the 2014 World Cup final.
Laura Russell (capt.), Toronto Nomads, Bolton, Ont.; Mary-Jane Kirby, Highland RFC, Brampton, Ont.; Olivia DeMerchant, Woodstock Wildmen, Mapledale, N.B.; Tyson Beukeboom, Aurora Barbarians, Uxbridge, Ont.; Maria Samson, Calgary Hornets, Calgary; Barbara Mervin, Velox RFC. Peterborough, Ont.; Latoya Blackwood, St. Anne de Bellevue, Montreal; Cindy Nelles, Oakville Crusaders/Belleville Bulldogs, Belleville, Ont.; Lori Josephson, Aurora Barbarians, Beaverton, Ont.; Alex Tessier, Montreal Barbarians, Sainte-Clotilde-de-Horton, Que.; Lisa Gauthier, St-Anne de Bellevue, St-Bernardino, Ont.; Andrea Burk, Capilano RFC, North Vancouver; Amanda Thornborough, Brandon Barbarians RFC, Brandon, Man.; Katie McNally, Velox Valkries, Guelph, Ont.; Julianne Zussman, Town of Mount Royal RFC, Montreal.
Tiffany Picketts, UVIC Vikes/Abbotsford Rugby Club, Abbotsford, B.C.; Julia Folk, Regina Rogues, Regina; DaLeaka Menin, Hornets, Vulcan, Alta.; Camille Provencal-Aube, Abenakis et CRQ, Sherbrooke, Que.; Jacey Murphy, Aurora Barbarians, Alliston, Ont.; Gillian Allen, Kirin, Saskatoon; Jess Neilson, Meraloma, Vancouver; Natasha Smith, Barrhaven Scottish, Ottawa.