You can map a permission level to replace it on your objects (i.e., sites, lists, documents, etc.) at the destination during a migration.
Index
Prerequisites
Before starting your migration, verify that you have the correct permissions for your operation.
For more information, see Microsoft administrative permissions.
How-to
Select Copy from the menu.
Select the type of copy you want to perform, then connect to a source and a destination.
Click Mappings on the top-right.
In the Mappings screen, select the Permission levels tab.
From the far-right column, select the Destination permission levels you want to map.
Drag and drop the permission level into the appropriate spot in the Destination column.
Click Save.
Default mapping behavior
By default, permission levels with the same name will automatically be mapped together.
Permission levels mapping affects how the permission levels are applied to your content during the migration. It does not affect the migration of the permission levels themselves.
During the migration of a site:Default permission levels will merge at the destination.
Custom permission levels with the same name will merge at the destination.
Custom permission levels with different names will always get copied as new.
Export and import
To save your mappings for future use or to use mappings from a previous session, you can export or import a mapping file.
Export - From the Mappings screen, select the Export permission level mappings icon to save the SGRM file to your preferred location.
Import - From the Mappings screen, select the Import permission level mappings icon to open your SGRM saved file.