How to rename a device in Android 4.3:

Turn your device ON and select Apps.

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Selects Settings icon. Note that settings icon may not be present on the first page and you may scroll the pages until you find the setting.
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Under settings click on More icon as shown in the picture below:

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Select About device present in bottom of the screen as shown below

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Now select the device name and enter the Device name whatever you want and click ok.

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