Remove Site Name from SERPs

I need help ensuring that Google no longer appends my website name to any of my blog-post listings. Every article currently shows up in Google as “Post Title | Site Name,” but I would like the listing to display only the post title itself for every blog post across the site... (Budget: £10 - £20 GBP, Jobs: CMS, Link Building, PHP, SEO, Web Design, Web Development, Website Management, WordPress)