there is one restriction with your broker, usually is 90 days
one with the fund company, different from each compony
you have to check the load type before you buy it,
after you buy it, you either keep it or hold it.
better check with your broker
another thing useful is (like BMO, not sure if others are the same)
that you buy the front load fund, they will waive the load.
but if you buy the same fund with back end load, you have to pay yourself
always check with your broker