Just follow the step by step instructions.
Step 1 Go to https://www.blogger.com and Sign in to your account
Step 2 From Blogger Dashboard enter into specific post or any static page where you want to disable or hide comment.
Step 3 now you would see at the right sidebar of writing panel or post editor Post Settings Option.
Step 4 Under Post Settings->Readers comments Post select Don't Allow, Show Existing or Don't Allow, Hide Existing
Step 5 And finally press on Done button. And check your selected post or page for seeing the effect. Your Blogger comment box is not visible.
If you want to allow comment again for that specific post just return and select "Allow"
If you want to disable comments in all your post and pages just go to Layout-Blog post (edit) and uncheck comments then save.
Read here on how to use Blogger, Facebook and Disqus comment system in blogs.