function convertRegularToRewardTokens(address _user, uint256 _amount)
        external
        onlyOwner
        validAmount(_amount)
        senderHasEnoughTokens(_amount, 0)
        isWhitelisted(_user)
    {
        balances[msg.sender] = balances[msg.sender].sub(_amount);
        rewardBalances[_user] = rewardBalances[_user].add(_amount);

        emit TransferReward(msg.sender, _user, _amount);
    }