Sharing Blogger blogs in Facebook shows blog title and article title

I have a blog on blogger (blogspot), and when I want to share an article on facebook, the name of the link (the gray fild under the image) appears as:

[Blog Name]: [Blog Post Title]

I would like to remove [Blog Name] from title so that it only appears as:

[Blog Post Title]

Is this possible?

I have found similar problem but regarding appearance on browser. How to remove blog name from page title in individual blog posts?

In template of our blog html code i have found:

<!-- Metadata Facebook -->
<meta expr:content='data:blog.postImageThumbnailUrl' property='og:image'/>
<meta expr:content='data:blog.title' property='og:site_name'/>
<b:if cond='data:blog.metaDescription != &quot;&quot;'>
<meta expr:content='data:blog.metaDescription' property='og:description'/>
<meta expr:content='data:blog.metaDescription' name='description'/>
<b:else/>
<meta expr:content='data:blog.pageName' name='description'/>
<meta expr:content='data:blog.pageName' property='og:description'/>
</b:if>
<meta expr:content='data:blog.pageTitle' property='og:title'/>
<meta content='article' property='og:type'/>
<meta expr:content='data:blog.url' property='og:url'/>
<script type='text/javascript'>

Unfortunately i have zero experience in html, so I do not know how to change it. We have tried experimenting with it, but whatever we did, blogger didn't save it.