How to Alter Constraint

Question

My Constraint:

CONSTRAINT ACTIVEPROG_FKEY1 FOREIGN KEY(ActiveProgCode) REFERENCES PROGRAM(ActiveProgCode),

I want to add in:

ON DELETE CASCADE

How can I add to the current constraint ACTIVEPROG FKEY1?

ON DELETE CASCADE

To constraint ACTIVEPROG_FKEY1, Think about ACTIVEPROG FKEY1, which is in Table ACTIVEPROG. 

Any help would be appreciated.