Can the school change the decision if the parent says that they don't want the child to be retain?

What do you mean? Can the child be held in the same grade for another year?

Is that what you are asking?

In my area there is a "hearing" when a child is held back and a decision is made by specialists in education and social work - a decision in the best interest of the child.

So, yes, the parent's wishes can be overriden.

Yes, but the parent would have to prove how they are going to change to make their child successful in the upcoming school year. We give them 6 weeks at the next grade level to show improvement, or they are sent back to the grade to repeat a second year.