Just like painting a fresh picture or painting over an old one.
In our environment there are many restricting thoughts,
which suggest that there are irreversible conditions for us.
These conditions only remain "unchangangable" as long as you THINK they are.
Aside from the unviversal laws - there are no hard rules.
"You have to grow from the inside out. None can teach you, none can make you spiritual. There is no other teacher but your own soul."
~ Swami Vivekananda