Global Page Template

Hi,
if i edit a section of the page template “elementor canvas” the changes are not overtaken by any page using this template.
I understand, that widgets can be saved as global, but i find no way to save sections or an entire page as global.
How can i manage to make changes in template pages that refreshes any page using this template?
The default theme i am using is Twenty fifteen.
Thanks for help!
Ronni