Can a weapon be used with a different stat if used as an improvised weapon?

@JeremyECrawford Can a weapon be used with a different stat if used as an improvised weapon? For example, a glaive used with dexterity.

— Ilya Rakhlin (@IRakhlin) March 25, 2016

The finesse property lets you use Str. or Dex. w/ a weapon attack. An improvised weapon doesn't also do this. #DnD https://t.co/w87SYblIfJ

— Jeremy Crawford (@JeremyECrawford) April 1, 2016