Should we change the water (10-25%) or will that dilute the nitrites that we are trying to convert into nitrate.?
Yes it would dilute the amount of nitrite. Im sure your wanting to get fish in there so you have something to look at other than a box of water. If you do a small water change like 10% this should give you a slight jump in getting the nitrites down to 0 and at the same time should impact your cycle just a small amount if there is any impact.
Your cycle is very important as thats what sets the stage for a healthy tank. Trying to rush the cycle to much can cause your tank to not be fully prepaird for fish when you finally do put fish in. The net result could be high levels of ammonia again or worse having fish deaths.