How to change the default input when error occur in struts validate method?

Question

In the struts-config.xml file,action element has a input attribute which used when the actionForm's validate method return some errors.

<action
  path="/somepath"
  attribute="someForm"
  input="/some.jsp"
  name="someForm"
  parameter="status"
  scope="request"
  type="cn.mycompany.struts.action.SomeAction"/>

But I want to change this input attribute when errors occur in the validate method,because I have more than one page submit to this action and I want it forward to the current submit page.

How can I do this,please help me.