I want to change the status at $ result, to get the data at $ result I use query builder, but there is an error like that

$results = ClientVendor::where('client_id','=', $request->client_id)
                                 ->where('vendor_id','=',$request->vendor_id)
        ->get();
        $results->status = $request->status;
        $results->save();
        return response()->json($results);

You cant do this because you call whole collection where is many elements. Call just single record, then you can update it.

When you use get() you call collection When you use first() or find($id) then you get single record that you can update.

Look at example:

$results = ClientVendor::where('client_id', $request->client_id)
                        ->where('vendor_id',$request->vendor_id)
                        ->first(); // this point is the most important to change
$results->status = $request->status;
$results->save();
return response()->json($results);;

Good luck!