Rule reminder

'Andare + pp' for obligation agrees in gender and number with the subject: 'il documento va firmato', 'la lettera va firmata', 'i documenti vanno firmati', 'le lettere vanno firmate'. Tense of 'andare' changes for past/conditional: 'andava fatto' (had to be done — imperfect), 'andrebbe fatto' (should be done — conditional), 'è andato fatto' is NOT used (compound tenses don't exist for this periphrasis in obligation sense).