Combine cherries, sugar, cornstarch, and salt in a medium saucepan; stir until well blended. Set aside for 10 minutes. Cook over medium heat 15 minutes or until thickened, stirring occasionally. Cool slightly.
Roll half of pastry to 1/8-inch thickness on a lightly floured surface; fit into a 9-inch pie plate. Spoon cherry mixture into pastry shell.
Roll remaining pastry to 1/8- inch thickness; cut into 3/4-inchwide strips, and arrange in a lattice fashion over filling. Trim edges; seal and flute. Bake at 450° for 15 minutes. Reduce heat to 400°; bake an additional 20 minutes. (Cover edges of pie with aluminum foil to prevent overbrowning, if necessary.) Cool before slicing.