diff --git a/doc/cpptraj.lyx b/doc/cpptraj.lyx
index 6641ba7a18..6c06584d01 100644
--- a/doc/cpptraj.lyx
+++ b/doc/cpptraj.lyx
@@ -13743,7 +13743,14 @@ change [parm <name> | parmindex <#> | <#> |
 
 \begin_layout LyX-Code
       bondparm <make1> [<mask2>] {setrk|scalerk|setreq|scalereq} <value>
- }
+\end_layout
+
+\begin_layout LyX-Code
+      {mass|charge} [of <mask>] {to <value>|fromset <data set>}
+\end_layout
+
+\begin_layout LyX-Code
+    }
 \end_layout
 
 \begin_deeper
@@ -14033,6 +14040,41 @@ setreq Set bond equilibrium lengths to <value>.
 scalereq Scale bond equilibirum lengths by <value>.
 \end_layout
 
+\end_deeper
+\begin_layout Description
+mass|charge Change mass or charge in specified topology.
+\end_layout
+
+\begin_deeper
+\begin_layout Description
+of
+\begin_inset space ~
+\end_inset
+
+<mask> Atoms to change mass/charge of.
+\end_layout
+
+\begin_layout Description
+to
+\begin_inset space ~
+\end_inset
+
+<value> Value to change mass/charge to.
+\end_layout
+
+\begin_layout Description
+fromset
+\begin_inset space ~
+\end_inset
+
+<data
+\begin_inset space ~
+\end_inset
+
+set> Use values in <data set> for mass/charge; must have the same number
+ of values as atoms selected by <mask>.
+\end_layout
+
 \end_deeper
 \end_deeper
 \begin_layout Standard
diff --git a/src/Exec_Change.cpp b/src/Exec_Change.cpp
index 4aa06b21b4..c87d3b8a7d 100644
--- a/src/Exec_Change.cpp
+++ b/src/Exec_Change.cpp
@@ -18,8 +18,8 @@ void Exec_Change::Help() const
           "\t  addbond <mask1> <mask2> [req <length> <rk> <force constant>] |\n"
           "\t  removebonds <mask1> [<mask2>] [out <file>]}\n"
           "\t  bondparm <mask1> [<mask2>] {setrk|scalerk|setreq|scalereq} <value>\n"
-          "\t  mass [of <mask>] {to <value>|fromset <data set>}\n"
-          "\t  charge [of <mask>] {to <value>|fromset <data set>}\n"
+          "\t  {mass|charge} [of <mask>] {to <value>|fromset <data set>}\n"
+          "\t}\n"
           "  Change specified parts of topology or topology of a COORDS data set.\n",
           DataSetList::TopArgs);
 }