I think it is a story worthy of interst and study by anyone interested in Louisiana history.
In mid or late May 1864 Grant told Canby to keep the 19th and 13th Corps in louisiana in case the Confederate tried tollowing up their victory over Banks.
However on June 22nd Grant changed his tune. He had just failed in the June 15-18 attacks and needed more men for the siege. So Canby withdrew the men from Morganza and sent them east.
During that interim period Canby had plans but I'm not clear what they were.