For 2014 Chevy Cruze, I have heard two different ways of replacing transmission fluid; drain and fill or flush and fill.
There are Chevy dealerships that only does flush and fill, but some said that GM recommends drain and fill.
So, which is true and why?

Drain is good enough every 60K miles. Flush replaces all fluid and drain does about half.

Drain & fill is good and Dexron VI (6) is recommended, the filter and gasket are also required.

I tend to agree with carfixer007. Personally, I'd do it every 50,000 but that'* just a preference.

Your manual wants you to "change" every time, which tells me a flush which gets most of it out. It calls for every 97,500 miles or 45,000 miles under the severe schedule.

6T45 used with 4 cylinder and 6T70 used with 6 cylinder engine trans filters are not serviceable (unless you split the trans case apart).