You may want to change (Apple ID settings) your Apple ID stored on your iPhone, iPad or iPod touch for various reasons. To do so, simply tap:
Settings > iTunes & App Stores > tap on your Apple ID. Sign out and log in with your new account info
Note that you will not lose any apps that are associated with your other Apple IDs. All apps or other content (videos, books etc.) that you purchased and downloaded by using any other Apple ID will remain on the iPhone/iPad until they are deleted by you. However, if you want to update an app you will need to have the Apple ID that you used to buy that particular app. This tip is also useful for changing/updating to a new email address for an Apple ID.