Generally speaking, making cuts in the secondary reeds is risky. However, there are times when it can help improve a call's sound. I agree with Mark that experimenting with cuts in the secondary reeds should be done with very small nicks in the reed to start with. Trying to make larger cuts similar to what would typically be put in the primary sound reed will often deaden the sound quality of a call.
I have found that putting a very small nick in the secondary reed of a call that will not break off of the high end of a yelp will sometimes make it easier to achieve that transition between the high and low end. If you are going to start making cuts in the secondary reeds of any call, however, you should be prepared to scrap the call if it doesn't work out. Once you have deadened the sound quality by cutting the reeds, it is almost impossible to bring back to sounding good.