First of al you have to make sure the mod_headers module is installed on the apache server.

In the http requests the cookies are on the header Cookie:

Cookie: name=value

Then you should use the directive:

RequestHeader add|append|edit|edit*|merge|set|setifempty|unset header [[expr=]value [replacement] [early|env=[!]varname|expr=expression]]

For more info look at the url:

https://httpd.apache.org/docs/2.4/mod/mod_headers.html

RequestHeader edit Cookie test ""

should do the job.

Try it.