diff --git a/src/gp/gp_XY.cdl b/src/gp/gp_XY.cdl
index f3331e0a15..800c10d1aa 100644
--- a/src/gp/gp_XY.cdl
+++ b/src/gp/gp_XY.cdl
@@ -70,6 +70,11 @@ is
       raises OutOfRange
       is static;
 
+  ChangeCoord (me: in out; theIndex : Integer) returns Real
+      ---C++: inline
+      ---C++: return &
+      raises OutOfRange;
+
   Coord (me; X, Y : out Real)  is static;
         ---C++: inline
         ---Purpose: For this number pair, returns its coordinates X and Y.
diff --git a/src/gp/gp_XY.lxx b/src/gp/gp_XY.lxx
index 32183e95ab..460bbb638c 100644
--- a/src/gp/gp_XY.lxx
+++ b/src/gp/gp_XY.lxx
@@ -47,6 +47,12 @@ inline Standard_Real gp_XY::Coord (const Standard_Integer i) const
   return (&x)[i-1];
 }
 
+inline Standard_Real& gp_XY::ChangeCoord (const Standard_Integer theIndex)
+{
+  Standard_OutOfRange_Raise_if(theIndex < 1 || theIndex > 2,NULL);
+  return (&x)[theIndex - 1];
+}
+
 inline void gp_XY::Coord (Standard_Real& X,
 			  Standard_Real& Y) const
 { X = x;  Y = y; }
diff --git a/src/gp/gp_XYZ.cdl b/src/gp/gp_XYZ.cdl
index 8e40c31a45..a775fdb70a 100644
--- a/src/gp/gp_XYZ.cdl
+++ b/src/gp/gp_XYZ.cdl
@@ -78,6 +78,12 @@ is
       raises OutOfRange
       is static;
 
+   ChangeCoord (me: in out; theIndex : Integer) returns Real
+      ---C++: inline
+      ---C++: return &
+      raises OutOfRange;
+
+
   Coord (me; X, Y, Z : out Real)  is static;
         ---C++: inline
         --Purpose: For this XYZ object, returns:
diff --git a/src/gp/gp_XYZ.lxx b/src/gp/gp_XYZ.lxx
index b060336abf..9a9ed2a754 100644
--- a/src/gp/gp_XYZ.lxx
+++ b/src/gp/gp_XYZ.lxx
@@ -50,6 +50,12 @@ inline Standard_Real gp_XYZ::Coord (const Standard_Integer i) const {
   return (&x)[i-1];
 }
 
+inline Standard_Real& gp_XYZ::ChangeCoord(const Standard_Integer theIndex)
+{
+  Standard_OutOfRange_Raise_if(theIndex < 1 || theIndex > 3,NULL);
+  return (&x)[theIndex - 1];
+}
+
 inline void gp_XYZ::Coord (Standard_Real& X,
 			   Standard_Real& Y,
 			   Standard_Real& Z) const