Creo Interactive Surface Design (Style) > Surfaces > Editing Surfaces using the Surface Edit Tool > Merging Knots
  
Merging Knots
In a Merge Knots operation, you merge the knots of a child surface and its parent surface. The current set of knots is used, including the number of rows and columns you have defined and dragged. The child surface knots near parent surface knots are aligned and merged.
 
* After you merge the knots of two surfaces, the child surface is automatically updated when the parent surface knots are changed.