Step 1 On Verifying your account page, return to Select Wlan Network page and add a new network.
Step 2 Type a line of random characters on Network SSID. Long press the characters and choose Share.
Step 3 On the pop-up page, long press Gmail and it will shows Gmail's App info. Choose Notification > App Settings.
Step 4 Tap three dots icon and choose Manage Account. You will see the below notification. Tap Continue to enter Settings.
Step 5 On Settings, choose Backup & Reset > Factory data reset. After the reset, Google account will be removed from the phone.