Windows Phone 7 and multiple Xbox Live accounts - How?

OK, this should be easy, but for some reason I can't figure it out...

Let's say I have a WP7 and I already signed in with one Xbox Live gamertag. Now I want to sign out and sign in to another existing Xbox Live gamertag (a different account). How do I do that?

@BitFlipper: Click on your gamertag on Windows Phone, then click on edit.  Scroll down for the instructions of changing the Live ID association.

As far as signing in an out like a console.  I don't believe that is supported.

@RLO:

OK, so let's say I have the following scenario: I just bought the "Gold Family" Xbox Live package, which  gives me 1 main account and 3 additional accounts. Each one of those accounts have their own Live ID (unique email address) and unique gamertag. But now I want to alternatively look at or edit any of those four accounts.

I noticed that I was able to add additional Live accounts to WP7, but I don't know how to display the associated Xbox gamertag for that account.

I realize this might not be a seamless experience, but what would be the easiest way to switch between them?

That is just crazy! No-one knows how to do this, or it can't be done? Apparently you can't delete the initial Windows Live account without doing a factory reset! Really?  All I want to do is switch to a different Xbox Live account.

having a similar issue.. i have two live acconts, one old one for xbox and then a new spamless one for messenger, what id really like to to is merge every aspect of them except for the actual mailbox, all the contacts, calender, all that stuff i'd like to merge.. linking is a step in the right direction but contacts are still separate and there is no option to merge them

i guess thats a pipedream though