Description
By default, FortiMail is configured in Gateway mode to send the quarantine report with the 'from address' as 'release-ctrl@hostname.domain'.
This article shows how the 'from address' can be changed.
Scope
FortiMail in Gateway mode only. v7.0 onwards.
Solution
The following screenshot shows the default mail settings for FortiMail configured in Gateway mode and with the hostname set to 'mail' and the local domain name of 'andy.lab'.
Using these settings, when a quarantine report is released it will be delivered to the original user with a 'from address' of 'release-ctrl@mail.andy.lab.'

The 'from address' can be modified to use 'release@andy.lab' by changing the 'Quarantine report template' as shown below.

After these changes are made, the released quarantine report will now be seen as coming from 'release@andy.lab'.
For FortiMail Cloud, the change must be applied under Domain & User -> Domain -> Advanced Setting -> Quarantine Report Setting -> Report template -> Template 'Domain setting' and select the template, in this case 'default-with-icons'.