Remove User from hierachy fields

RemoveUserFromHierachyFields.cls

Id userId = '005i000000XXXXX';

List<String> fields = new List<String>{'Sales_Director__c','Account_Coordinator__c','Account_Services_Representative__c','Program_Director__c','Sales_Director__c','Placement_Manager__c','Inside_Sales_Representative__c','New_Family_Placement_Manager__c'};

User[] users = [
    SELECT Id, Name, Account_Coordinator__c, Account_Services_Representative__c,Inside_Sales_Representative__c, New_Family_Placement_Manager__c,Placement_Manager__c, Program_Director__c, Sales_Director__c
    FROM User
    WHERE Account_Coordinator__c = :userId
    OR Account_Services_Representative__c = :userId
    OR Inside_Sales_Representative__c = :userId
    OR New_Family_Placement_Manager__c = :userId
    OR Placement_Manager__c = :userId
    OR Program_Director__c = :userId
    OR Sales_Director__c = :userId];

List<User> updateUsersList = new List<User>();

for(User user : users){
    if(user.Account_Coordinator__c == userId){
        user.Account_Coordinator__c = null;
    }
    if(user.Account_Services_Representative__c == userId){
        user.Account_Services_Representative__c = null;
    }
    if(user.Inside_Sales_Representative__c == userId){
        user.Inside_Sales_Representative__c = null;
    }
    if(user.New_Family_Placement_Manager__c == userId){
        user.New_Family_Placement_Manager__c = null;
    }
    if(user.Placement_Manager__c == userId){
        user.Placement_Manager__c = null;
    }
    if(user.Program_Director__c == userId){
        user.Program_Director__c = null;
    }
    if(user.Sales_Director__c == userId){
        user.Sales_Director__c = null;
    }
    //system.debug('user: ' + user.Name);
    updateUsersList.add(user);
}

system.debug('updateUsersList: ' + updateUsersList);
update updateUsersList;