Someone has created Master page using design manager. Now I want to modify this master page to make some changes.
Which is the best way to do it without breaking the original master page?
SharePoint Stack Exchange is a question and answer site for SharePoint enthusiasts. It only takes a minute to sign up.Sign up to join this community
If you would like to continue the development further on the master page, I would suggest export the design package and import and apply in a developer site.
Production -> Export Package -> Developer Site -> Import Package -> Make Changes
Customize the new developer site and export and import the package from the developer site to the production package.
Developer Site -> Export Package -> Production Site -> Import Package
This will give you a site to test and continue working for any future changes.
Thanks and hope this helps Deepak