Can a pleading be amended after a demurrer has been sustained?

Amending a pleading after a demurrer has been sustained merely by omitting the deficient allegations and nothing more could be called a sham. (Sanai v. Saltz (2009) 170 Cal.App.4th 746, 768.) "[T]he trial court has discretion to deny leave to amend when the proposed amendment omits or contradicts harmful facts pleaded in a prior pleading unless a showing is made of mistake or other sufficient excuse for changing the facts. Absent such a showing, the proposed pleading may be treated as a sham." (Ibid.)