Your decision to sell the fund should not be based on market volatilities.
As you know, the day-to-day market behavior is not rational. Therefore, buying and selling with market fluctuations will usually lead to impulsive and irrational decisions, which will never make you money. You will tend to buy and sell at the wrong times leading to more losses than gains.
Instead, there are other criteria, which you should consider to know whether it is time to sell your fund or not. These generally include the following:
a) If you need money then of course there is no choice but to sell
b) If the fund is not performing as well as its peers/benchmark
c) If you are not confident of the future prospects of the economy
d) If you have to rebalance your portfolio
e) If there is a change in taxation policy
f) If the fund characteristics/manager has changed