Modify H1 tags with child theme

Hi, I've noticed that in Gridalicious there are three different H1 tags: <h1 class="site-title"> <h1 class="assistive-text">Primary Menu</h1> <h1 class="entry-title"> I would like to maintain only the "entry-title" as H1 tag, because I think it would be far better for SEO purposes. Could it be handled with child theme? Could you please have some suggestions to accomplish this customization? Thank you for your great support, regards Francesco