The article addresses a very important issue of changing the procedural roles of participants in criminal proceedings and the ability to use previously provided explanations or testimony in separate proceedings. These problems involve multi-person cases, where there are cases of exclusion of certain acts or some of the defendants for separate proceedings. The views expressed in the case-law and the literature have been presented in the study. The admissibility of the testimony of the witness has been questioned in cases when it had been submitted before he became defendant, and in a separate trial he has not exercised his right to refuse to testify on the basis of art. 182 § 3 of the Code of Criminal Procedure.