There is no need to deliberately cut your weights down and boost up your reps. This is an old school approach to getting ready for contests. Conventional thought is that we know higher reps don't = ripped to shreds body. Diet and cardio do. So keep your weight training as is.
Now as you drop bodyfat, thusly overall bodyweight, you may notice dips in your strength...this is a situation where you may drop your resistance so it is still "heavy" relative to your new weight. The only other reason to drop weights during precontest is if you are dealing with minor or nagging injuries, overuse, etc and want to proceed with caution as to avoid a full blown contest ending injury.
A cut is the same principle, just without any carb, water, and electrolyte manipulation for stage presentation. Remember, the key is in cardio and diet. Adjust your macros, particularly making a drop in your carbs and add some cardio. Over time, additional manipulation of macros is necessary. Slow and steady wins the race...
These are just general guidelines, and more specific feedback can be obtained by asking more specific questions, or check out the contest prep, nutrition, or fat loss sections.
Fat Loss
http://forum.bodybuilding.com/forumdisplay.php?f=16
Nutrition
http://forum.bodybuilding.com/forumdisplay.php?f=13
Contest Prep
http://forum.bodybuilding.com/forumdisplay.php?f=15