Email Distribution List owners can modify group membership in their Distribution Lists.
This is done by selecting the Distribution List in the WSLH Global Address List > Right-click that > Properties > Modify Members... > Add or Remove the needed members > OK > OK
If an owner is not able to modify or would like ability to manage their list, please put in a TeamDynamix ticket to request that.
Currently general users are not able to edit Distribution Lists. General user membership is granted per owner approval. A TeamDynamix ticket is required for that modification request.