TanDEM-X resolution

I extracted interferometric surface height (ISH) using TanDEM-X data. my steps was
interferogeram> Topographic phase removal> filter goldstein> unwarpping> georefrencing> phase to height
my TanDEM-X resolution is about 2.17 * 3.1 meters. how can I change to 10 meters? which step? which step is suitable?

either by multi-looking after the interferogram generation (I would suggest that) or alternatively enter a final pixel resolution in the Range Doppler Terrain Correction step (should be perfored after phase to height by the way, regardless of the resolution).