How to change a route name rails 4

path option along with resource must help.

resources :posts, :path => 'blogs' do
  resources :comments
end

This will change all /posts and /post to /blogs/ and /blog.

If you want to change your route's helper methods such as posts_path to blogs_path and new_post_path to new_blog_path etc, you can change it with as tag.

resources :posts, :path => 'blogs', :as => 'blogs' do
  resources :comments 
end

Or yet better, you can specify the controller and route blogs directly as:

resources :blogs, controller: 'posts' do
  resources :comments
end

This is the awesomeness of Rails! :)