Available is similar to Open. Open is a different concept from Reserve. Reserve is related to Restaurant. 
Role can be used for Purpose. Purpose is related to Rescue. Rescue is a synonym of Free. Key can Free. 
Available <--SimilarTo--> Open <--DistinctFrom--> Reserve <--RelatedTo--> Restaurant 
Role --UsedFor--> Purpose <--RelatedTo--> Rescue <--Synonym--> Free <--CapableOf-- Key 