Multiple Conditions IF AND THEN statement SAS

data FINAL;
set FINAL;
if Visit="DC" and DIAGCANC ="N/A" then DIAGCANC="MISSING";
if Visit="MH" and MEDHIST ="N/A" then MEDHIST="MISSING";
if Visit="OLR" and OLRESP ="N/A" then OLRESP="MISSING";
if Visit="TLR" and TLRESP ="N/A" then TLRESP="MISSING";
run;

This is my code for an IF AND THEN statement. This format of code (If and then) has been used earlier in my code and has worked fine. For some reason I can't understand, there is no change made in the output when i run this. There are also no errors.

Here is the output I get for a little more insight.

https://imgur.com/a/EiLx0AS

Thanks.