I own a sears lawn tractor with a 42 inch cutting deck. On the right side there is a handle with a button on top. To lower the deck you push the button down and push forward to lower the deck. Pushing the button will not lower the deck. Thank You

If it is connected by a cable then likely the cable is broken inside. Replace it.

When you pust the botton try momentarily lifting or pull on the handle and then it should lower.