xxxxxxxxxx
public function (Request $request){
$geturl = $request->all();
$yoururl = 'blabla.com';
$replace = str_replace($geturl, $yoururl, $geturl);
// str_replace(find, replace, url_you_want_to_replace)
xxxxxxxxxx
public function (Request $request)
{
$geturl = $request->path();
$string = 'whatever';
$replace = str_replace($geturl, $string, $geturl);
return response()->json(['Replaced' => $replace]);
}