This has been an issue for a while I've just never reported it. Running the latest release of Residence on bukkitdev.

When we do /resadmin delete (res) to force-delete a residence, we're prompted with /res confirm/deny, but it immediately says something about no permission to delete.

When I transfer the ownership of the residence to myself and then delete, the confirmation works fine.

Unless you own the residence, you need to use /resadmin to confirm - e.g. /resadmin confirm

As javacraft stated

It wouldn't be an issue but the message says to use "res confirm". The message should reflect the appropriate usage.