Usually I write my descants without really thinking about having someone “sing” them, but rather to be played by a second person on the organ bench. This one can be sung, or played, or both, and is available here in two keys. The harmony remains unchanged, so no advance notification to the congregation is required.
Neither is a live recording. Both are MIDI output from Sibelius (music engraving software), but will show you how this descant sounds. The sample in G features a violin solo, and the Eb sample is piano-only, but you can do anything you want.