Can I change the request params in backing beans?

[Hailong Zhang]

I want to change the request params in the backing bean method.
For example:
<h:commandLink value="test" action"myBean.test">
<f:param name="a" value="1" />
</h:commandLink>

When user click the link, myBean.test() will be invoked.
Can I change the request param values in myBean.test()?
I mean, if I can change the value of "a" to "2" or add a new param so that the new param value will be sent to the next page.

Thanks!