How to make Cesium re-render one particular tile?

Hello.

I can select the tiles I need to re-render, spanning a rectangle over the surface with my mouse cursor, but how to actually ask Cesium to re-render then using new GET-parameters for the .pnts file?

You can set tile.expireDate = Cesium.JulianDate.now() to force a re-request of the pnts file.