When an admin changes the color scheme for a project, portfolio or member it overrides any colors previous set. When and admin makes these changes it also pushes those updated colors to all members of the organization.
To update the color of a portfolio:
Click on the three dots next to the portfolio name
Select set portfolio color
To update the color of a project:
Click on the small dot to the left of the project name
To update the color of a member:
Go into the teams space
Hover of the member's square
Select the circle in the top lefthand corner
