SQL & PL/SQL

Is there an htp command that will erase any output that has been put to a screen? I have a program that uses radio buttons for various options. I have a section of text that displays at the top of every page regardless of what radio button is selected. However, when I do some error checking with and If Statement, I just want the error message to appear by itself. I want the "header" text I set up for all the other pages to go away when my error checks display an error.

Here is an example of one of my error checks:

ELSIF detail_to_date is null
THEN
htp.htmlOpen;
vvchk_errormsg('**** ERROR on Input ****', 'End Date Not Entered', 'Select the browsers BACK button to re-enter values.');
htp.htmlClose;
goto end_of_program;


Is there something like an htp.clear I can put just before the errormsg output to give it a fresh screen? Thanks!