Some people say that there is really nothing we can do about our destiny ... that God has determined it in advance (predestination).
True, he has laid the tracks, and he has limited our option to only two tracks. He has predestined that all on Track 1 go to hell and that all on Track 2 go to heaven.
But, we can choose, with our own free will, the track we want.
We can look out the window and heed the signs at the stops and platforms along the way, which are our decision points.
To change, we simply get off the train on Track 1 and walk across the platform to the train on Track 2, as explained in God's character. Besides getting us to the desired destination, the train on Track 2 has softer seats and nicer passengers.
God has chosen (election) the category of people that will go to heaven – the ones on Track 2 – but each individual chooses (with his own free will) whether or not he wants to be a part of that category.
Failing to make a decision to change means that the person deliberately chooses to remain with the group on Track 1.
By what right (justification) can someone simply get off the train on Track 1 headed for hell and get on the train on Track 2 headed for heaven? Because Jesus Christ offers a fully paid ticket, purchased by his substitution death on the cross.
We don’t pay for the Track 2 ticket with our own money or works. It's a free gift from God, more than we deserve (grace).