"To change the mentality" means to alter someone's way of thinking or their beliefs, usually in a way that brings about a different perspective, attitude, or behavior. Full definition
This lag can be due to a combination of things, he said, from changing the mentality of publishers, to the fierce competition between reading devices. (publishingperspectives.com)
I found it hard to try and change my mentality in one week and kept thinking «I can't believe I'm not eating carbs». (simplycantara.com)
The whole part of this process is that you are changing your mentality from spending to saving. (debtroundup.com)