John 20:23 If you forgive anyone's sins, their sins are forgiven; if you withhold forgiveness from anyone, it is withheld.
Matthew 16:19
I will give you the keys of the kingdom of heaven. Whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven."
So, God forgives us our sins in the Sacrament of Reconciliation, through the words of His priests.
IF you are forgiven in the confessional booth it is just as available if there is no priest on the other side of the partition.
I can get the same forgiveness by humbling myself privately before HIM and confessing TO HIM and asking for HIS forgiveness. Forgiveness is NOT CONVEYED by the catholic priest, it is given BY GOD ALONE because JESUS said GOD will forgive when we confess to HIM, because HE HAS THE POWER TO FORGIVE.