LE event to show transfer and benefit eligible date

Summary:

What LE would take place when a employee changes position under the same assignment and goes from a non benefit eligible role to a benefit eligible role?

Content -

The employee was rehired into a role on 1/16/22 then transferred on 11/4/23 under same assignment to a new position

Ending the old role -2 role for the benefits to pull is not possible because its under the same assignment

So my question is since the retiree benefits ( old position )should be active until 11/30/23, should we be updating the Primary Assignment to the -2 new position eff. 12/1/23 ( considering one month of wait for the new benefits to become active ) or the date of transfer for the transfer LE to be processed ( which is 11/4/23)?