diff --git a/doc/software-manual.tex b/doc/software-manual.tex
index 8c486cf1800f138cf1ee92a25fca9c7b92085ac3..df690d2fc9813b86a6299c2a716fa17a0a019a71 100644
--- a/doc/software-manual.tex
+++ b/doc/software-manual.tex
@@ -5804,7 +5804,7 @@ Specifies sii_num_units_in_shutter_interval for single entry.If multiple entries
   \\
   \Option{SEINNPostFilterActivationCancelFlag} &
   \Default{false} &
-  Specifies the persistence of the target neural-network post-processing filter established by any previous NNPFA SEI message with the same nnpfa_id.
+  Indicates that the NNPFA SEI message cancels the persistence (true) or follows (false).
   \\
   \Option{SEINNPostFilterActivationPersistenceFlag} &
   \Default{false} &