Abrogation in the Qur'an

Good evening!

In the Islamic reading for tomorrow, I was very interested in the idea of abrogation (naskh). Abrogation, in regards to the Qur’an, “refers to the process by which some of the Qur’an’s earlier verses are said to have been annulled by later revelations”(Saeed 170). Some of the Muslims actually rejected this idea of abrogation because they perceived it to imply that there was some sort of inconsistency throughout the Qur’an. However, other Muslims were able to see abrogation as an indication that the Qur’an is adaptable and can essentially be adjusted. I liked this idea because abrogation shows that it is wrong of some Muslims to assert that, “once a ruling is present in the Qur’an, it cannot be reinterpreted and remains an ideal for all times and places”(Saeed 171). Just because the method of achieving a certain goal is changed does not mean that the moral purpose behind it also changes. Thus, abrogation is able to challenge the idea that the Qur’an is a text of “set rules, fixed for all times and places”(Saeed 171) and is instead something that is adaptable. By understanding abrogation in regards to the Qur’an, one is able to understand further that the Qur’an is able to be reinterpreted. But when is it exactly known to annul earlier verses of the Qur’an? Is there a certain amount of time that needs to pass or a certain kind of revelation that needs to occur in order to abrogate certain rulings? Does anyone know where I can find these instances of abrogation in the Qur’an? Let me know what you think!