CREATE TABLE Medication (Code VARCHAR, name VARCHAR)
CREATE TABLE Prescribes (Patient VARCHAR, Medication VARCHAR)
CREATE TABLE patient (name VARCHAR, SSN VARCHAR)

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