Hi,
havent tested this myself but from reading this blog from Marek it looks like setting NULL should 'un-delete' it:
https://community.superoffice.com/en/developer/blog/soft-delete-%E2%80%93-the-undo-revolution/
"But they are not gone from the database, and the new Recycle Bin in the Sales client will show them. There you can Recover them, which simply means that the deletedDate is reset… and voilá, the record is back."
It shouldnt have any side-effects to un-delete them like this, as deletedDate is set to mark them for actuall deletion after a given time (14 days?).
//Eivind