Restrict email changing

Question

How to disallow or restrict users from changing their email ids to a new email id from edit profile,  after successfully registering with original email id?

Update 1-
In order to perform any action its asking to confirm email.
That would be ok :)

Thanks for taking a look.

Comments

Sorry, I meant for Q2A. What solution you got?

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First changed email id.. Next, was not abke to edit a question. Message was displayed please confirm your email. Eventhough i was able to change email, but could not perform task. But when change itself it should ask to confirm :)

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Thank you. That's an okay behaviour :)

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Ok boss :)....