Once the Trustee's Sale has taken place; the house is FORECLOSED. It belongs to the bank. The Homeowner is done, finished!
Now, in about 4 to 6 weeks, the house should be listed by a Realtor who will sell it for the Bank.
The only exception is that some States have laws for REDEMPTION and if the homeowner can come up with the money, they can redeem the mortgage. It doesn't happen too often.