What does Eliza's act of fetching Higgins's slippers symbolize in Pygmalion?

It
symbolizes her loyalty and devotion to Prof. Higgins.

Higgins has
successfully trained Eliza to be a lady of quality in much the same way that you'd train a puppy
to fetch your slippers. Despite her outward demeanor as a duchess, Eliza is still instinctively
deferential...