When You're mobile is unlocked by pattern if you unlock the pattern . so follows this steps....
(1)First switch off u,r mobile than switch on with press key volume up/down.
(2)Press the Volume down button to select "Recovery mode."
(3)Use the volume buttons to scroll to "wipe data/factory reset" and press the Power button to select it.
(4)Scroll down to "Yes - erase all user data" and press the Power button to select it.
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