When removing a subform instance, avoid subform occurrence violations. You cannot remove a subform instance if it has reached the minimum number of instances. When a subform reaches the minimum number of instances, the JavaScript debugger displays an error message:
If the end user is allowed to remove every instance of a subform, reset the minimum number of instances to 0 before attempting to remove an instance. Otherwise, the script should prevent any attempt to remove subform instances beyond the minimum number.
Reference_Syntax.removeInstance( INTEGER param )
Form Model

removeInstance