Do you have 6 Miki’s sitting in your roster? Or what about all those useless Horgall’s you’ll never ascend? Wouldn’t it be nice if we can trade them in for Telescopes or Mysterious Tonics, and all the other wonderful 4* mats out there?
Hit the 
and reply with “SIGNED!” to demand Small Giant (or to beg, we don’t mind begging) for this feature.