The rtf file is text-based, so if you know the code for the blank page, you can process it.
Check this.
filename sample "c:\temp\class.rtf";
ods rtf file=sample;
proc print data=sashelp.class;
run;
ods rtf close;
data _null_;
infile sample;
input;
put _infile_;
run;
However, rather than deleting the blank page, it would be better to modify the program so that the blank page is not generated.
If you can provide the rtf with the blank page or its executable program, you may get more advice.