The likelihood is that she loaned the Blackstaff to the White Council but promised not to take it back, the White Council has to voluntarily return it to her, which is never going to happen unless Harry intervenes.
She can’t retrieve it or order Harry to retrieve it, but if it were to end up in Harry’s Possession (which it will, all major magical artefacts seem to) he Can give it back to her.
The whole magical artefact thing is so bad that when the White Council eventually find out about him they will tell him that Bob is number 2 on the most wanted list of dangerous magical artefacts and Bob could easily say “that’s flattering, I don’t even make the top five in Harry’s collection” which is true, Eye of Balor, Spear of Destiny, the Shroud, The Placard, the Crown of Thorns, Amorrachius, Bob.
And he has previously been custodian of the sword of Faith and a blackened Denarius at the same time, as well as an original Star Wars poster.