To update Android Market app to Google Play app on your Android device, follow the steps below. Open Market and change settings to Auto-Update Apps (go to Market Menu – Settings and enable ‘Auto-Update Apps’). Then update all apps by going to ‘My Apps’ section.
Close Android Market App and start it again. Accept the terms and conditions and tap on ‘Continue’ option to upgrade Android Market to Google Play. That’s it! For your information, Google Play is an integrated destination place for apps, books, movies, and music and can be accessible on Android devices and on the Web.