5th dnd – Is it considered to drop its concentration on a creature?

Under the effects of Blink and in the ethereal plane, can you give up a concentration spell to affect a creature in the material plane?

As part of wink "You can only affect and be affected by other creatures in the Ethereal plan."

As part of Concentration You can end the concentration at any time (no action required)

A teammate is shot in your Nauseating Radiance stunned and will start his turn. If you finish your concentration before your turn, you will also remove levels of a creature's depletion.