I worked at two companies where Elliott came in. They will get a seat on the board. They will threaten management with a proxy vote to oust them if they don't concede to terms. They will sell off what they consider to be under performing or non core assets. They will cut costs and they will layoff.
https://www.businesswire.com/news/home/20190122005513/en/Elliott-Management-Sends-Letter-Board-Directors-eBay