Update/fix the date

[Flip]

DATA INCORRECT1_3;
SET DENTAL1_2;
DATE=DATEPART(FILMDATE);
YEAR=YEAR(DATE);
WHERE CYCLE=3;
IF (YEAR LT 1975) OR (YEAR GT 1980) THEN
newdt = input(cat(substr(put(date, date9.), 1, 5), '1977'), date9.);
put newdt date9.;
run;