If you are looking merely to change the sentence to an active voice, you simply locate the verb in the sentence and change the verb from passive to active. For example, the verb in question here is "was associated," and so we change it to "associated" (retaining the past tense). Thus, we have: "Section 3.05 of multiple relationships, where the person closely associated with the psychologist." I will post a link below to an excellent tutorial demonstrating the use of the passive voice. In brief, with the passive voice, the subject of the sentence (grammatically) is the object of the verb's action. In the (more common) active voice, the subject of the sentence is the subject of the verb as well.