If you want to use an instance as a restore destination (without backing up the instance), you can manually modify the user name.
On a UNIX platform, the UNIX user name is set for an instance during a full backup of an FSbased backupset. The user name is the operating system user that owns the PostgreSQL data, tablespaces, and archive log directories.
From the navigation pane, go to Protect > Databases.
The Instances page appears.
Click the instance that you want to modify the user name for.
The instance page appears.
On the Overview tab, click Edit.
The Edit PostgreSQL instance dialog box appears.
Click Connection details.
In the UNIX user name box, change the user name.