I can\'t find a way to change a relationship type in Cypher. Is this operation possible at all? If not: what\'s the best way achieve this result?
The answer from Michael Hunger is correct but it still need with in this cypher query.
WITH can be used when you want to switch different operation in one cypher query.
http://docs.neo4j.org/chunked/stable/query-with.html
MATCH (n:User {name:"foo"})-[r:REL]->(m:User {name:"bar"})
CREATE (n)-[r2:NEWREL]->(m)
SET r2 = r
WITH r
DELETE r