You may need to blend in batches. Have someone help you (or slowly use a ladle to fill the blender) pour soup into the blender. Do not fill the blender more than 2/3 of the way full. It's OK to blend in batches. Leave the cap of the blender very slightly open so the steam can escape. Stand away from the blender when opening the lid after you're done blending. Remove this batch from the blender and place in spare pot or a large bowl. Repeat with the remaining soup, then you can add the coconut milk and season as needed.