Table schema:
CREATE TABLE Prescribes (Patient VARCHAR, Medication VARCHAR); CREATE TABLE Medication (Code VARCHAR, name VARCHAR); CREATE TABLE patient (name VARCHAR, SSN VARCHAR); CREATE TABLE patient (name VARCHAR)

Question: Find the names of patients who are not using the medication of Procrastin-X.
SQL: SELECT name FROM patient EXCEPT SELECT T1.name FROM patient AS T1 JOIN Prescribes AS T2 ON T2.Patient = T1.SSN JOIN Medication AS T3 ON T2.Medication = T3.Code WHERE T3.name = 'Procrastin-X'