Lately come up this idea that Trump will claim that they essentially changed the regime because the people got changed. He can very well claim it for his mission accomplished, and people can only roll with it for nor Trump neither the further events will care about definitions.
But just to make it clear to ourselves.
Regime is not equal to leadership. The regime is not the people.
Regime is the political and socio-economic system of a state. The people running this system can and do change - die of old age or for example in countries with democratic procedures other people get elected into the positions of power and offices. In the UK with the hereditary head of state position and elected governments the faces changed hundred times over while the regime stands solid.