shake up – v. to make important changes or series of changes in the way a company or other organization is organized or run. Shake-up as a noun is hyphenated.

overdue – adj. something that should have happened or been done before now

opportunity – n. an amount of time or a situation in which something can be done

challenge – n. a difficult task or problem: something that is hard to do

response – n. something that is done as a reaction to something else