Creo Simulate > References > Sketcher > Dimensioning Sketcher Geometry > Replacing a Dimension
  
Replacing a Dimension
You can replace an existing Sketcher dimension with an equivalent one so that the new dimension retains the symbolic dimension (sd#) of the original. Replacing a dimension is useful when you want to preserve additional data associated with the original dimension (for example, geometric tolerance symbol or extra text added in Drawing mode).