PL/SQL :: Delete Data Not Required Retaining Rows

CREATE TABLE "TEST_JET" ("K1" NUMBER, "K2" NUMBER, "K3" NUMBER, "K4" VARCHAR2(1)) ;
REM INSERTING into TEST_JET
Insert into TEST_JET (K1,K2,K3,K4) values (1,2,3,'I');
Insert into TEST_JET (K1,K2,K3,K4) values (1,2,3,'U');
Insert into TEST_JET (K1,K2,K3,K4) values (1,2,3,'D');
Insert into TEST_JET (K1,K2,K3,K4) values (1,2,2,'U');
Insert into TEST_JET (K1,K2,K3,K4) values (1,2,2,'D');
Insert into TEST_JET (K1,K2,K3,K4) values (1,3,5,'I');
Insert into TEST_JET (K1,K2,K3,K4) values (1,6,7,'U');
Insert into TEST_JET (K1,K2,K3,K4) values (1,6,7,'D');
Insert into TEST_JET (K1,K2,K3,K4) values (1,6,7,'T');
[code]....

based on the above result set , for a particular group ,only that op will be retained which comes out in the query . say for example , we have got 1,2,3,'D' for group 1,2,3

now since we have got the D Operation from the above query , i don't need the other two rows .i.e.
(1,2,3,'I');
(1,2,3,'U');

what is the best way to delete the data we don't want retaining the rows we want ,using a single sql statement . Also , for the result set row 7,7,7,T I first need to delete the group containing T operation, and insert two new rows .i.e. 7,7,7,D and 7,7,7,I .