The hard way to remove a label in SAS is to list out all of the labels one-by-one, like this

data mylib.mydataset;
  set mylib.mydataset;
  label varA='';
  label varB='';
  label varC='';
run;

But if you don’t know all of the variables ahead of time, or just want something cleaner/faster, you can do this

proc datasets library=mylib nolist;
  modify mydataset;
  attrib _all_ label='';
quit;