Conversion is a type of Transformation. Improvement is a type of Transformation. Improvement is related to Good. Good is a synonym of Decent. 
Combine is a type of Interact. Have is a type of Interact. Have is related to Employ. 
Conversion --IsA--> Transformation <--IsA-- Improvement <--RelatedTo--> Good <--Synonym--> Decent 
Combine --IsA--> Interact <--IsA-- Have <--RelatedTo--> Employ 