decrease, diminish, lessen, fall - decrease in size, extent, or range; "The amount of homework decreased towards the end of the semester"; "The cabin pressure fell dramatically"; "her weight fall to under a hundred pounds"; "his voice fell to a whisper"

alter, change, modify - cause to change; make different; cause a transformation; "The advent of the automobile may have altered the growth pattern of the city"; "The discussion has changed my thinking about the issue"