The greeting you want to change is likely the Path '0' Menu greeting in a CCR tree. You will have to find the correct Table, and CCR tree that has to be changed.
Login to the mail and go to AA and then Lines. Fine the table associated with the lines being answered for the Administration Dept ( L001, 002, 003 or whatever )
Then back out to the Table prompt, and go into that table and disable the corresponding CCR tree.
After the tree is disabled, go back to the first prompt field ( MBOX AA OTHR ) and choose OTHR, then CCR, then ADMIN. Choose CCR tree 1, press change, and change the PATH 0 menu recording, and any of the other transfer points that are no longer relevant.
Don't forget to press the END prompt after you are done, and SAVE as the correct tree number. Then go back and retrace your steps to re-enable the CCR tree in the appropriate Table.