Conversion is a type of Exchange. Exchange is related to Give. Give is related to Appoint. Appoint is related to Person. 
Convention is a synonym of Agreement. Agreement is related to Mortgage. 
Conversion --IsA--> Exchange <--RelatedTo--> Give <--RelatedTo--> Appoint <--RelatedTo--> Person 
Convention <--Synonym--> Agreement <--RelatedTo--> Mortgage 