Once Google Analytics has processed the data it collects, you can still recover any data that was filtered out.
some Analytics features fundamentally alter how data is collected or processed in your account in ways that cannot be reversed, you should duplicate the original view before making changes.
Read more here: https://support.google.com/analytics/answer/3256366
Create a copy of a view
Because some Analytics features fundamentally alter how data is collected or processed in your account in ways that cannot be reversed, you should duplicate the original view before making changes. Always keep original views unchanged and add filters or other reporting features to the duplicate views. This lets you use the original view as the canonical source, or reference point, for all the data you’re collecting in that property, and customize the other views to meet specific reporting needs. Learn more about views and about properties.
How to copy a view
Views are associated with properties. Duplicated views can only be associated with the same property the original view. You need Edit permission to copy a view. To copy a view:
Sign in to Google Analytics..
Click Admin, and navigate to the view you want to copy.
In the VIEW column, click View Settings.
Click Copy view.
Give this a new view name.
Use a distinct name, so you can distinguish it from the original view.
Click Copy View.
What gets copied
Settings and features controlled at the view level (like filters, Goals, users and their permissions) are duplicated in copied views. Cost source links and shared assets (like annotations, Segments, and alerts) are not duplicated into copied views.