I live in Indiana and currently pay child support on 2 kids my oldest being 18 1/2 and attending college in the fall . His college will be paid for through scholarships and looks like he will receive a full ride. He is currently working full time and in the fall plans to reduce his hours by half but will still be making a substantial income of $800 a month living expenses. And still living with his mother. . Do I need to continue support or can I ask for a reduction ? Since college is paid and he is working

You can always ask for a reduction based on changed circumstances.

How is your support Order written? In NY it's until the child is, basically, out of school and scholarships or anything else have no bearing on support.

You need to check your original orders as Indiana has flip flopped over the years. Also its not automatic that it goes until 21. The child has to apply for it with a plan on continued education. You need to check your original orders to see how it applies to you.

His earnings will probably not affect anything. As long as he is eligible for support, you will probably have to pay.