i want the following output using one to many merging

[Mounika2]

data SV (RENAME=(VISIT=TERM));
input PT VISIT$9. STDT: YYMMDD8.;
format STDT is8601da.;
datalines;
101 screening 2017-02-10
102 screening 2017-02-12
103 screening 2017-02-16
104 screening 2017-02-11
run;

data RI;
input PT TERM$13. STDT: is8601da.;
format STDT is8601da.;
datalines;
101 randomization 2017-02-23
102 randomization 2017-02-22
103 randomization 2017-02-20
104 randomization 2017-02-21
run;

data DM (RENAME=(ACTARM=TERM));
input PT ACTARM$ RFSTDTC is8601da.;
format RFSTDTC is8601da.;
datalines;
101 drugA 2017-03-05
102 drugB 2017-03-10
103 drugA 2017-03-06
104 drugB 2017-03-01
RUN;

DATA DS;
INPUT PT TERM$ STDT IS8601DA.;
FORMAT STDT IS8601DA.;
DATALINES;
101 complete 2017-09-23
102 complete 2017-09-20
103 complete 2017-09-24
104 complete 2017-04-22
RUN;

i got the following output by combining the above datasets;

data want;
set ri sv dm;
if STDT= " " then STDT=RFSTDTC;
run;
proc sort data=want;
by pt term;
run;

output

Pt    TERM                 STDTC            RFSTDTC

101 screening           2017-02-10

101 randomization     2017-02-23

101 drugA                  2017-03-05      2017-03-05

101 complete             2017-09-23
102 screening            2017-02-12

102 randomization     2017-02-22

102 drugB                  2017-03-10        2017-03-10

102 complete            2017-09-20
103 screening           2017-02-16

103 randomization    2017-02-20

103 drugA                 2017-03-06        2017-03-06

103 complete            2017-09-24
104 screening           2017-02-11

104 randomization    2017-02-21

104 drugB                 2017-03-01        2017-03-01

104 complete            2017-04-22

what i want is

Pt    TERM                 STDTC            RFSTDTC

101 screening           2017-02-10     2017-03-05

101 randomization     2017-02-23    2017-03-05

101 drugA                  2017-03-05      2017-03-05

101 complete             2017-09-23     2017-03-05
102 screening            2017-02-12   2017-03-10

102 randomization     2017-02-22    2017-03-10

102 drugB                  2017-03-10        2017-03-10

102 complete            2017-09-20        2017-03-10

103 screening           2017-02-16       2017-03-06

103 randomization    2017-02-20       2017-03-06

103 drugA                 2017-03-06        2017-03-06

103 complete            2017-09-24        2017-03-06
104 screening           2017-02-11      2017-03-01

104 randomization    2017-02-21       2017-03-01

104 drugB                 2017-03-01        2017-03-01

104 complete            2017-04-22        2017-03-01

[Jagadishkatam]

Please try the below code on existing dataset

data want2;
merge want(drop=RFSTDTC) dm(keep=pt RFSTDTC);
by pt;
run;