If you want to change a user's role in a project, you can follow these steps to do it. 

1. Go to Manage tab and then click Manage Projects (Figure 1)

 Figure 1 

2. Click number link under Active User column associated with target project. It will go to Active Users page of selected project (Figure 2).

 Figure 2  

3. You can see a list of the users in the project with their roles. You can simply set the new role for the target user(s), then click Save Changes button (Figure 3).

 Figure 3 

4. The page will refresh and the role of the user(s) will be updated (Figure 4).

 Figure 4