I failed the CILS B1 Cittadinanza: what happens now?

You retake the whole exam. For B1 Cittadinanza you cannot keep the parts you passed: if you fail even one skill, you redo all four at a later session.

CILS calls this the ban on "capitalizzazione". There are six sessions a year; you register again at a centre before the deadline of the session you choose.

Before trying again, look at which part was weak and work on it: listening, reading, writing and speaking are worth 12 points each.