It depends

http://finance.google.com/finance?q=MCHFX+

It depends on what kind of investor you are and what is the purpose on this investment. If it is for a long term, aggressive growth investment, you could either sell at a rebound and try to buy back at a lower price; or, if you're not comfortable with your market timing ability, just let it sit. In either of the cases above, you should consider additional investment at current or future lowered price. Of course, if you have changed your view on China or the fund, then you should get out.