Create a studio quality background

I have the model. All I need is to create a professional background (white with some light or a light blue) and add it to the photo. Near that, you should place the advertised product. I have uploaded the original photo, the product and the background pattern (could be similar) along with an example of how I would like it to look. If you could edit the shoulder to look real, continuous, that would be great, but it is not necessary. Do not alter the picture's light and shadows as that stage will be completed by someone else. Thanks!