Water changes will make the water parameters move toward the water parameters in your source water.
If nitrate is 20 ppm in the aquarium, and 0 in the tap, and you change 50% of the water, it will go to 10ppm.
Same for Ammonia, and most anything else.
If ammonia is high, I would work out why though, as it normally would not be, if you added fish, keep an eye on your water, same for replacing filter media, or not dechlorinating water used to fill or clean equipment.
You can reduce the amount of ammonia produced in a normal aquarium by feeding less (Even if you feed correctly normally, it will slow down ammonia production while the cycle catches up). but if it comes from something decaying, or not having been cleaned, the real solution is going to be to remove that.
put some bare rooted pothos plants (just put the roots in the water and the plant above the water) the plant will draw the nitrates out of the water. and when the plant is established it is also very decorative. you still need frequent water changes but I have well water with high nitrates and pothos plants also I use SeaChem Safe in my barrel water and my water is excellent.