EXHIBIT 99.5.2
INSTRUCTION TO REGISTERED HOLDER AND/OR
FORM OF BOOK-ENTRY TRANSFER PARTICIPANT FROM OWNER
FOR AT&T ELIGIBLE NOTES
AT&T CORP.
OFFER TO EXCHANGE AND CONSENT SOLICITATION
FOR ITS OUTSTANDING
5.625% NOTES DUE 2004 (CUSIP NO. 001957AU3)
6.75% NOTES DUE 2004 (CUSIP NO. 001957AM1)
7.75% MEDIUM-TERM NOTES, SERIES A DUE MAY 15, 2025 (CUSIP NO. 00206QAP9)
8.00% MEDIUM-TERM NOTES, SERIES A DUE MAY 15, 2025 (CUSIP NO. 00206QAN4)
6.50% NOTES DUE 2029 (CUSIP NO. 001957AW9)
FRN MEDIUM-TERM NOTES, SERIES A DUE 2054 (CUSIP NO. 00206QAE4)
PURSUANT TO ITS EXCHANGE OFFER AND CONSENT SOLICITATION
DESCRIBED IN THE PROSPECTUS DATED , 2002
To Registered Holder And/Or Participant Of The Book-Entry Transfer Facility:
The undersigned hereby acknowledges receipt of the Prospectus dated
, 2002 (the "Prospectus") and the accompanying Letter of Transmittal
and Consent (the "Letter of Transmittal"), that together constitute the
"Exchange Offer," and hereby instructs you, the registered holder and/or
book-entry transfer facility participant, as to the action to be taken by you
relating to the Exchange Offer with respect to the AT&T Eligible Notes held by
you for the account of the undersigned.
The aggregate face amount of the AT&T Eligible Notes held by you for the
account of the undersigned is (fill in amount):
<Table>
$
--------------- 5.625% Notes Due 2004 (CUSIP No. 001957AU3)
$
--------------- 6.75% Notes Due 2004 (CUSIP No. 001957AM1)
$ 7.75% Medium-Term Notes, Series A Due May 15, 2025 (CUSIP
--------------- No. 00206QAP9)
$ 8.00% Medium-Term Notes, Series A Due May 15, 2025 (CUSIP
--------------- No. 00206QAN4)
$
--------------- 6.50% Notes Due 2029 (CUSIP No. 001957AW9)
$ FRN Medium-Term Notes, Series A Due 2054 (CUSIP No.
--------------- 00206QAE4)
</Table>
With respect to the Exchange Offer, the undersigned hereby instructs you
(check appropriate box):
[ ] To TENDER, and CONSENT to the Note Amendment with respect to, the
following AT&T Eligible Notes held by you for the account of the undersigned
(insert principal amount of AT&T Eligible Notes to be tendered and with respect
consent is given, if any):
<Table>
$
--------------- 5.625% Notes Due 2004 (CUSIP No. 001957AU3)
$
--------------- 6.75% Notes Due 2004 (CUSIP No. 001957AM1)
$ 7.75% Medium-Term Notes, Series A Due May 15, 2025 (CUSIP
--------------- No. 00206QAP9)
$ 8.00% Medium-Term Notes, Series A Due May 15, 2025 (CUSIP
--------------- No. 00206QAN4)
$
--------------- 6.50% Notes Due 2029 (CUSIP No. 001957AW9)
$ FRN Medium-Term Notes, Series A Due 2054 (CUSIP No.
--------------- 00206QAE4)
</Table>
[ ] NOT to TENDER any AT&T Eligible Notes held by you for the account of
the undersigned.
If the undersigned understands and acknowledges that in order to
participate in the Exchange Offer, holders of AT&T Eligible Notes will be
required to consent to the proposed amendment (the "Note Amendment") described
in the Prospectus under "Description of the Note Amendment" to the indenture,
dated as of September 7, 1990, between AT&T Corp. (the "Company") and The Bank
of New York, as trustee, as amended, under which the AT&T Eligible Notes were
issued, with respect to all tendered AT&T Eligible Notes accepted for exchange
in the Exchange Offer, upon the terms and subject to the conditions set forth in
the Exchange Offer. If the undersigned instructs you to tender, the undersigned
also instructs you to consent to the Note Amendment to the extent the
undersigned's AT&T Eligible Notes are accepted for exchange.
If the undersigned instructs you to tender, and consent with respect to,
the AT&T Eligible Notes held by you for the account of the undersigned, it is
understood that you are authorized to make on behalf of the undersigned (and the
undersigned, by its signature below, hereby makes to you) the representations
and warranties contained in the Letter of Transmittal that are to be made with
respect to the undersigned as a beneficial owner, including but not limited to
the representations, that (i) the holder is not an "affiliate" of the Company,
and (ii) if the undersigned is a broker-dealer that will receive New AT&T Notes
for its own account in exchange for AT&T Eligible Notes, that such AT&T Eligible
Notes were acquired as a result of market-making activities or other trading
activities, and that the undersigned acknowledges that it will deliver a
prospectus meeting the requirements of the Securities Act in connection with any
resale of such New AT&T Notes, provided that by acknowledging that it will
deliver and by delivering a prospectus meeting the requirements of the
Securities Act in connection with any resale of such New AT&T Notes, such
broker-dealer is not agreeing that it may be deemed an "underwriter" within the
meaning of the Securities Act of 1933, as amended.
SIGN HERE
<Table>
SIGNATURE(S):
------------------------------------------------------------
NAME(S) (PLEASE PRINT):
------------------------------------------------------------
ADDRESS:
------------------------------------------------------------
------------------------------------------------------------
------------------------------------------------------------
TELEPHONE NUMBER:
------------------------------------------------------------
TAXPAYER IDENTIFICATION OR
SOCIAL SECURITY NUMBER:
------------------------------------------------------------
DATE:
------------------------------------------------------------
</Table>
2