Login at MedAll.org
Click my profile
Click "click for preview" on the right hand side of the poster if you have already uploaded the poster (or the little form icon then edit poster if you are yet to upload any poster)
Click the poster upload icon and upload new PDF.
Once you have been invited to upload your poster, you are unable to edit the poster authors or abstract from that which the organisation has uploaded. If you would like to do this please contact the organisation running the event.