To delete a blend shape deformer
- Do either of the following:
- In the Blend Shape Editor, click the Delete button on the Blend Shape node you want to remove.
- Select the blend shape deformer node in the Attribute Editor, then press
or 
(Mac OS X), or select Edit > Delete.
The selected deformer nodes are all deleted. However, the base object still has the tweak node as an input node, so any tweaks you might have made are preserved.