In the command prompt window, run the following command:
cmd4 config -in c:\"" -who nnnn -UserName xxxx -Password yyyy
where nnnn is the GN4 name of the user to whom you are deleting the list, xxxx is the name of a GN4 user who can logon to system with sufficient permissions to perform this operation and yyyy is the password.
Note: the above connects to the default connection: should you want to specify the connection or server name, see cmd4 examples.
See also
Remove global autocorrect list
Import personal autocorrect list from file