To buy another coin which is relatively cheaper and better. You can always sell and buy but you have to know how to move your position.
Or you can also sell to buy a coin which has better technical analysis.
To do this, the best and simpliest way to do is:
Waiting for waves of dumps when altcoins fall to nearly 20 percent or lower; then you can step in with nearly zero risks. Doing this also help you to maximize your marginal profits, and reduce waiting time to take profits too.