The law gives you certain rights if you rent from the Housing Executive. You have more rights if you are a secure tenant than you do if you are an introductory tenant.
You can swap your tenancy with another secure social tenant. You need to get your landlord's permission to swap, but they can only refuse in certain cases.
You can add someone else to your tenancy. But, you need your landlord's permission to do this and your landlord can refuse in some circumstances. You don't have to add people who live with you to your tenancy.