We all know that everywhere inside this universe, time flows naturally forward. That's true in the general case but not everything in this universe can be placed under such a general case.

Lets take the case of one of the most exotic cosmic objects, black holes. A black hole is usually formed from the death of a supergiant star. When a star expires it's lifetime, it explodes in a marvellous burst of glowing gas and dust called a supernova. During this process if the mass of the dying star was less than 3 solar masses it would become a neutron star but if it is greater than that it would turn into this cosmic monster called a black hole...

Read more at http://futurestica.com/blog/2017/05/08/time-direction-yes-can-ever-changed/