You can add relationships in RENXT, some users find they are unable to if they are not users with Supervisor rights.
Article
Number:113791
Products:
Raiser_s_Edge_RE
The following must be marked in the Security groups your users are associated with in the RE database under Admin > Security: 1) All Relationship types, they are allowed access to add, have the box marked under the ADD column 2) The "ADD" box must also be marked on the constituent row