Hello Ray,
This can be done by adding an AD object picker parameter to the Deprovision Custom Command.
To add the parameter:
- Launch Adaxes Administration Console.
- In the Console Tree, expand your service node.
- Navigate to Configuration\Custom Commands and select the Deprovision Custom Command.
- In the Result Pane on the right, activate the Parameters tab and click New.
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- Select AD object picker and click Next.
- Specify a parameter name and display name.
- Click Next.
- Configure what objects will be available for selection when executing the command.
- Enable the Allow empty value checkbox.
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- Complete the wizard and save the changes.
You need to use a value reference to pass the parameter value to actions in the Custom Command. For more details about value references, please see this help article: https://www.adaxes.com/help/?ValueReferences.ValRefFormat.html.
In the Deprovision Custom Command, you need to modify the built-in action set that grants full access rights to the user’s manager so that the value of the parameter is used instead.
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- Replace the If the ‘Manager’ property is not empty condition with the If <parameter> <value> condition and select If <parameter> is not empty.
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- Replace the actions in the action set with the Modify Exchange properties action and specify the value reference to the parameter as a trustee for Full Access and Send As delegation.
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- Save the changes.
Finally, the action set should look something like this: 
If you need to remove all existing trustees from the Mailbox Rights list when the value of the parameter is left blank, this can only be done using a PowerShell script. Please, take a look at this script from our repository: https://www.adaxes.com/script-repository/remove-all-trustees-from-full-access-list-s559.htm. The modified action set that also removes trustees from Mailbox Rights should look something like this:
If you need any assistance with modifying the script to meet your needs, please let us know, we will gladly help.