What happens when you copy content to an existing page?

I am trying to use the Multisite Content Copier, but I want to know what happens if I am copying content to a site that already has a page available. Is the content replaced or will the copy fail?

I created a page "A", but then I created new content and I want to copy page "A prime" to the multisite but have it replace page "A". Will the copy procedure fail or will page "A" just be replaced with the "A prime" content?