Does correcting the intention after performing a righteous deed with an impure intention restore the reward for that deed, or has the reward ceased with the completion of the deed?

Actions performed with corrupt intentions (like showing off) receive no reward, as the Prophet, peace and blessings be upon him, said: "Indeed, actions are by intentions, and for every person is what he intended." A valid action requires a sincere intention solely for the sake of Allah. The time for the intention is at the beginning of the action. If an action lacks a sound intention until its end, there is no reward for it. The regret and repentance of its doer do not accrue the reward for the action that had a corrupt intention, but he will be rewarded for his regret and repentance.