I can't change materials I was making a scene in blender and I wanted to change the texture from "Material_1" to "Material_2". It lets me change it but when I go to rendered view the part looks the same. can someone please help me
Having a material as part of the list of materials for an object does not mean that it is applied to it.

In edit mode, select the material you want to use, then select the faces where you want the material to be and press Assign