The answer depends on what they withdrew the money for, and what agreements you may have signed with PNC.
If it was just to fund your account, then it should be very easy to reverse the transaction.
If, on the other hand, it was to buy securities, and those securities have already been purchased, then you may have to pay certain transaction and other fees to liquidate the securities and get the cash back.
You should review the account documents that you signed or agreed to, and consider talking to an attorney that handles securities law matters. You can use the lawyer directory to find one locally.