Cook Frozen Vegetables According To Package Directions. Drain. In A Saucepan, Melt Butter Over Medium Heat; Saute Onion And Mushrooms Until Tender. Stir In Flour, Salt, Pepper And Sage. Combine Milk, Bouillon And Water. Slowly Pour Into Saucepan, Stirring Constantly. Cook And Stir Until Mixture Boils. Reduce Heat And Simmer 2 Minutes. Stir In Chicken, Pimiento And Parsley. Spoon Into Six Individual Casseroles. Roll And Cut Pastry Into Circles 1 In. Smaller Than Top Of Casseroles. Place Atop Of Filling. Bake At 425 Degrees F For 12-15 Minutes Or Until Crust Is Lightly Browned.