CREATE OR REPLACE PROCEDURE YourProcedureName 
(p_Subscriber_ID IN NUMBER,
 p_Threshold IN NUMBER,   -- number of 'unbroken' days allowed while still having unbroken eligibility
 p_Effective_Date OUT DATE,
 p_Term_Date OUT DATE) AS

-- variable declaration
v_Effective_Date DATE;
v_Term_Date      DATE;
v_New_Eff_Date   DATE;

-- cursor for finding a valid earlier record
CURSOR c_Valid_Record (a_Sub IN NUMBER, a_Threshold IN NUMBER, a_Date IN DATE) IS
  SELECT max(effective_date)     -- max() in case multiple valid records are present
    FROM YourTable
   WHERE SUBSCRIBER_ID = a_Sub
     AND a_Date - TERM_DATE <= a_Threshold;

BEGIN

-- get dates for record with highest TERM_DATE for this subscriber
  SELECT a.EFFECTIVE_DATE, a.TERM_DATE
    INTO v_Effective_Date, v_Term_Date
    FROM YourTable a
   WHERE SUBSCRIBER_ID = p_Subscriber_ID
     AND TERM_DATE = (SELECT max(TERM_DATE) 
                        FROM YourTable b 
                       WHERE b.SUBSCRIBER_ID = p_Subscriber_ID);
 
  LOOP
    -- Get Effective_Dtae from previous period
    OPEN c_Valid_Record(p_Subscriber_ID, p_Threshold, v_Effective_Date);
    FETCH c_Valid_Record INTO v_New_Eff_Date;
    -- Exit the loop when no valid previous period is found 
    EXIT WHEN c_Valid_Record%NOTFOUND;
    CLOSE c_Valid_Record;
    -- Set Effective Date equal to the date that was retrieved
    v_Effective_Date := v_New_Eff_Date;
  END LOOP;

  -- Close the cursor if it's still open
  IF c_Valid_Record%ISOPEN THEN
    CLOSE c_Valid_Record;
  END IF;

  p_Effective_Date := v_Effective_Date;
  p_Term_Date := v_Term_Date;
END;