Is this someone you want to take to Member status instead of having them make a certain number of posts? The setting that determines when someone becomes a member is based on the number of posts they make. This setting is in the general settings of your control panel in the Miscellaneous Options section.
If you're wanting to keep your default member status # of posts and are just making an exception for this person then you'll need to find their member file and manually edit it (FTP).
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Doug
darksaber.hispeed.comI am altering the deal. Pray I don't alter it any further.
--Darth Vader, The Empire Strikes Back