What investors should do when there is more volatility in the market

U.S. stocks are bouncing back after the market experienced its worst day in two years on Monday, but the average investor may still be understandably spooked. Over a three day losing streak, the S&P 500 dipped more than six per cent before rallying again Tuesday, up 1.6 per cent in midday trading.
Source: ctv business
What investors should do when there is more volatility in the market