How to avoid persisting new object when oneToMany connection?

There is a three lines in returnreason-table and I don't want more lines there. User just choose one of the three reasons and I want only id to rma-table. Now it inserts a new line to reason-table every time when inserting new rma. I can take relation off between the tables but I wonder if there is better solution to avoid inserting new lines when persisting rma object? If I take cascadeType off from the class Rma, it is not helping/working. Then I got an error message, that jpa found an object, which is not persisted or something like that.

errormessage if I took cascadetype.ALL off

java.lang.IllegalStateException: During synchronization a new object was found through a relationship that was not marked cascade PERSIST: com.entity.Returnreason[ returnreasonId=null ].

public class Rma implements Serializable {
@ManyToOne(cascade = CascadeType.ALL)
private Returnreason returnreasonReturnreasonId;

public class Returnreason implements Serializable {
@OneToMany(mappedBy = "returnreasonReturnreasonId", cascade = CascadeType.ALL)
private Collection<Rma> rmaCollection;