1) Navigate to the contact whose privacy relationship you'd like to modify and right-click on the their entry.

2) Point to "Change Privacy Relationship" and choose the privacy relationship that you would like to assign to this contact.

TIP: An overview of the different privacy relationships offered can be found in the article Overview of privacy relationships in Skype for Business.

Outcome

The privacy relationship for the chosen contact has been changed. This will apply on all of your devices using TTU Unified Communications.