My schema post default is Blog posting but I want change it to article. What can I do?

There is a way to override using a WordPress filter to change the output of the default markup. But, I don’t recommend it for this for a couple reasons. The main reason, have a look at http://schema.org/BlogPosting notice the type hierarchy: Thing > CreativeWork > Article > SocialMediaPosting > BlogPosting. That means a BlogPosting is a subtype of http://schema.org/Article and Google already knows enough to figure out it is also a type of Article. This is supported in Google’s guidelines, #2 Use the most specific applicable type and property names https://developers.google.com/search/docs/guides/intro-structured-data#technical-guidelines.