"Find a new steward" is an objective in the side quest "Reluctant Steward" in Elder Scrolls V: Skyrim - Dragonborn.
You will need to find a new steward for Neloth from Raven Rock. He says that they are in awe of him. Head there and find out.
Time to talk with people and find someone who will take on this "Honor." Talking with various people around Raven Rock will see the general reluctance to take on this position. A few people will point you toward the Retching Netch to find someone who might just be interested.
The quickest way is to head into The Retching Netch. Go inside it and look for Drovas Relvi.