public void FreeAnnotationBoxesInstanceUids()
When the Print SCP is requested to create a Film Box, and if an Annotation Display Format ID is specified, the Print SCP will also create one or more Annotation Boxes, based on the Value of that Attribute. This is true given that the Basic Annotation Box SOP Class is supported on the Association. An array of the SOP Instance UIDs of these Annotation Boxes is kept internally. This method frees the memory allocated for that array. Once this method is called, a call to the method GetAnnotationBoxesCount will return 0. This of course does not mean that no Annotation Boxes are referenced by the current Film Box.
For an example, refer to Associate.