If you want to replace a document from your portfolio, simply:

1. Go into your portfolio, select the item you want to replace and click ‘Edit’ on the top right corner of the screen.
2. Click ‘replace work’  icon on the right hand side of the screen.
3. Then click ‘upload files, select the file you want the current one to be replaced by and wait until it uploads.
4. Do not forget to click ‘done editing‘ to save your changes!