lessen

(verb) decrease in size, extent, or range. Synonyms: decrease, diminish, fall. Examples: "The amount of homework decreased towards the end of the semester." "The cabin pressure fell dramatically." "Her weight fell to under a hundred pounds." "His voice fell to a whisper."

(verb) make smaller. Synonyms: decrease, minify. Examples: "He decreased his staff."

(verb) wear off or die down. Synonyms: subside. Examples: "The pain subsided."