To put it another way, a thing or person is often seen as having a "defining essence" or a "core identity" that is unchanging, and describes what the thing or person really is. In this way of thinking, things and people are seen as fundamentally the same through time, with any changes being qualitative and secondary to their core identity (e.g. "Mark's hair has turned gray as he has gotten older, but he is still the same person"). But in Whitehead's cosmology, the only fundamentally existent things are discrete "occasions of experience" that overlap one another in time and space, and jointly make up the enduring person or thing. On the other hand, what ordinary thinking often regards as "the essence of a thing" or "the identity/core of a person" is an abstract generalization of what is regarded as that person or thing's most important or salient features across time. Identities do not define people, people define identities. Everything changes from moment to moment, and to think of anything as having an "enduring essence" misses the fact that "all things flow", though it is often a useful way of speaking.
In that line of thinking, how are changes described?
qualitative and secondary to their core identity

During the Pacific War Funafuti was used as a base to prepare for the subsequent seaborn attacks on the Gilbert Islands (Kiribati) that were occupied by Japanese forces. The United States Marine Corps landed on Funafuti on 2 October 1942 and on Nanumea and Nukufetau in August 1943. The Japanese had already occupied Tarawa and other islands in what is now Kiribati, but were delayed by the losses at the Battle of the Coral Sea. The islanders assisted the American forces to build airfields on Funafuti, Nanumea and Nukufetau and to unload supplies from ships. On Funafuti the islanders shifted to the smaller islets so as to allow the American forces to build the airfield and to build naval bases and port facilities on Fongafale. A Naval Construction Battalion (Seabees) built a sea plane ramp on the lagoon side of Fongafale islet for seaplane operations by both short and long range seaplanes and a compacted coral runway was also constructed on Fongafale, with runways also constructed to create Nanumea Airfield and Nukufetau Airfield. USN Patrol Torpedo Boats (PTs) were based at Funafuti from 2 November 1942 to 11 May 1944.
From what time span were USN Torpedo Boats stationed at Funafuti?
2 November 1942 to 11 May 1944

The Kabul Shahi dynasties ruled the Kabul Valley and Gandhara (modern-day Pakistan and Afghanistan) from the decline of the Kushan Empire in the 3rd century to the early 9th century. The Shahis are generally split up into two eras: the Buddhist Shahis and the Hindu Shahis, with the change-over thought to have occurred sometime around 870. The kingdom was known as the Kabul Shahan or Ratbelshahan from 565-670, when the capitals were located in Kapisa and Kabul, and later Udabhandapura, also known as Hund for its new capital.
The decline of what empire allowed the rule of the Kabul Shahi empire?
Kushan