Is it possible to step into the same river twice?

"You cannot step twice into the same river." 

Heraclitus of Ephesus  c. 535–c. 475 BC.

Is it possible to step  into the same river twice? Whether it be the Seine or the Thames or a backwater stream, it is not possible; for a river is an entity continuously in flux. The river is more like a process than a thing. When you step into the river you are stepping into a stage in the river rather than a thing called the river.

This 'river-stage' that you step into is a momentary aggregation of all the water molecules which lie between the river’s banks at a certain time. It is one of a huge multiplicity of temporal stages or parts which collectively constitute the 4 Dimensional object known as the river.

If you understand yourself to be stepping into the same river twice you are employing  a 3 dimensional ontology (nature of being) - the river in this view is an enduring object having no temporal parts. If you employ the 4 dimensional ontology the river is a collection of temporal parts which do not endure.

It follows,  that when I step into the river I am not stepping into a thing bur a process.