Address your request to 'FMail', 'AreaMgr' or 'AreaFix' (without quotes).
Enter your password for AreaMgr on the subject line.

In the body of the message to AreaMgr (with area FMAIL_HELP as an example) :

FMAIL_HELP         Connect area FMAIL_HELP
FMAIL_HELP /R      Connect area FMAIL_HELP and rescan all messages
                   in the message base
FMAIL_HELP /R=50   Connect area FMAIL_HELP and rescan at most 50 messages

-FMAIL_HELP        Disconnect area FMAIL_HELP

%+ALL              Connect all available areas
%-ALL              Disconnect all areas

%COMPRESSION ZIP   Change the compression method used for your mail to ZIP
                   (or ARC/ZIP/LZH/PAK/ZOO/ARJ)
%PASSWORD ABCDEF   Change your AreaMgr password to ABCDEF (password should
                   be at least 5 characters and at most 16 characters long)
%PKTPWD QRSTUV     Change your packet password to QRSTUV (password may be
                   at most 8 characters long)
%NOTIFY ON         Turn NOTIFY messages on
%NOTIFY OFF        Turn NOTIFY messages off

%HELP              Request this message
%LIST              Request a list of areas available to you
%BLIST             Request a list of areas available to you in
                   binary format (*.BCL file)
%QUERY             Request a list of areas for which you are active
%UNLINKED          Request a list of areas to which you are not connected

%RESCAN            Request a rescan of all new areas
%RESCAN=50         Request a rescan of at most 50 messages per area for
                   all new areas

%PASSIVE           Temporarily disable all areas. This means that you won't
                   receive any echo mail anymore unless it is addressed to
                   you personally (only if the sysop on this node has
                   entered your name correctly in the Node Manager). You
                   will still be allowed to send echo mail to this system
                   in areas to which you are connected.
%ACTIVE            Make your node active again.

[---]              Everything below the tear line is ignored

You can also use the -H, -L, -Q and -U switches on the subject line.

