Using match with namespace

I have namespace "admin" and controller "Accounts" with namespace
"Admin".
And Controller Accounts has method change_password.
I want have route admin/accounts/change_password.

For this I try using member

namespace :admin do

resources :accounts do
  member do
    get :change_password
  end
end

end

But my method "change_password" does not have identificator(1) (admin/
accounts/1/change_password/).

What can I use for this?