This mode is used when the new installation and the old installation are on the same host, in two separate locations. In this mode, sm_migrate migrates all customizations (non-binary files that have been modified or introduced by you in the old installation) from the old installation to a new installation.
Note:
All files that were modified or newly introduced in the old installation must be present only under the BASEDIR/smarts/ directory.
When you use the --sitemod option, the migration utility will migrate all customized old files for all user created locals.