The European Parliament and the Council review proposals by the Commission and propose amendments. If the Council and the Parliament cannot agree upon amendments, a second reading takes place.

In the second reading, the Parliament and Council can again propose amendments. The Parliament has the power to block the proposed legislation if it cannot agree with the Council.  

If the two institutions agree on amendments, the proposed legislation can be adopted. If they cannot agree, a conciliation committee tries to find a solution. Both the Council and the Parliament can block the legislative proposal at this final reading.  

This diagram is a simplifying schema of the co-decision procedure leading to Community law