Existing　research　on　maintenance　policy　optimization　typically　assumes　that　the　failure　intensity　functions　of　the　system　under　maintenance　are　only　modified　due　to　the　effectiveness　of　maintenance.　However,　in　practice,　they　may　also　be　modified　based　on　innovation　replacement.　This　paper　considers　a　system　with　finite　operating　time.　It　assumes　that　the　exact　time　of　occurrence　of　the　innovation-related　modification　is　unknown.　The　system　is　preventively　maintained　once　it　reaches　a　certain　age,　and　failures　that　occur　between　such　preventive　maintenance　actions　are　fixed　with　minimal　repair.　This　paper　proposes　a　framework　to　optimize　the　preventive　maintenance　policies　pre-　and　post-innovation　replacement　with　an　objective　to　minimize　the　total　expected　cost.　Numerical　examples　are　employed　to　illustrate　the　applications　of　the　proposed　methods.