set the field to None instead

        current = shared.sd_model.sd_checkpoint_info

        try:

            if self.hr_checkpoint_info is not None:

                del self.sampler

                self.sampler = None

                sd_models.reload_model_weights(info=self.hr_checkpoint_info)

                devices.torch_gc()

            return self.sample_hr_pass(samples, decoded_samples, seeds, subseeds, subseed_strength, prompts)

        finally:

            del self.sampler

            self.sampler = None

            sd_models.reload_model_weights(info=current)

            devices.torch_gc()