In addition to Fisher’s changes, which we’re guessing extended well beyond this one scene, Harrison Ford also changed the final interaction between himself and Carrie Fisher.
It would appear that a great deal of the Empire Strikes Back script was changed while shooting.
While it’s been often stated that Ford improvised the line “I know,” the truth is he actually worked out the change with the screenwriter before hand, as would obviously have been done in this case as well.