ADF Lov valu can be reset as below (Lov default value set to null) .
Presentation
UI component
<af:selectOneChoice value="#{bindings.BILLING_CITY.inputValue}"
label="#{bindings.BILLING_CITY.label}"
shortDesc="#{bindings.BILLING_CITY.hints.tooltip}"
id="BILLING_CITY1Id" autoSubmit="true"
binding="#{pageFlowScope.xxxBean.billingPostalCode}"
showRequired="true">
<f:selectItems value="#{bindings.BILLING_CITY.items}"
id="selectItems1"/>
</af:selectOneChoice>
Bean
setEL("#{bindings.BILLING_CITY.inputValue}",null);
public static void setEL(String el, Object val) {
FacesContext facesContext = FacesContext.getCurrentInstance();
ELContext elContext = facesContext.getELContext();
ExpressionFactory expressionFactory =
facesContext.getApplication().getExpressionFactory();
ValueExpression exp =
expressionFactory.createValueExpression(elContext, el,
Object.class);
exp.setValue(elContext, val);
}