If an attachment denies their involvement with your project they will be removed from your project profile page and you will not be able to add them again.
If the denial was made in error, that person will have to go to your project profile page and click the link at the bottom where it says “Are you involved in this project?”. This will allow them to submit a request to be added.
Once you’ve received this request, you can confirm their involvement. Once you have confirmed, they will be added to your project profile page.