SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549



                                    Form 6-K

                            Report of Foreign Issuer

                      Pursuant to Rule 13a-16 or 15d-16 of
                       the Securities Exchange Act of 1934


                       for the period ended 11 June, 2004


                                    BP p.l.c.
                 (Translation of registrant's name into English)


                 1 ST JAMES'S SQUARE, LONDON, SW1Y 4PD, ENGLAND
                    (Address of principal executive offices)


     Indicate  by check mark  whether the  registrant  files or will file annual
     reports under cover Form 20-F or Form 40-F.


              Form 20-F        |X|          Form 40-F
                         ---------------               ----------------


     Indicate by check mark whether the registrant by furnishing the information
     contained in this Form is also thereby  furnishing  the  information to the
     Commission  pursuant to Rule 12g3-2(b) under the Securities Exchange Act of
     1934.


                    Yes                            No        |X|
                         ---------------               ----------------



                       BP AND AAR AGREE CHANGE TO SHARE

                          PAYMENT DATES FOR TNK STAKE


BP and Alfa, Access and Renova (AAR) completed their sale and purchase agreement
relating to TNK-BP on 29 August 2003. BP and AAR today agreed to change the
dates on which BP is due, under the terms of that agreement, to issue AAR with
three tranches of BP p.l.c. shares, each tranche with a value of US$1.25
billion.


The issue dates have been changed from 29 August 2004, 29 August 2005 and 29
August 2006 to 20 September 2004, 20 September 2005 and 20 September 2006,
respectively.


The issue dates have been moved in order to avoid BP's third quarter ex-dividend
date falling within the calculation period for determining the number of BP
p.l.c. shares to be issued to AAR in each tranche, thereby reducing the
potential for volatility during that period. There is no incremental cost to BP
or its shareholders as a result of this change in issue dates.



                                    - ENDS -



                                         SIGNATURES


Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.



                                         BP p.l.c.
                                        (Registrant)



Dated: 11 June, 2004                               /s/ D. J. PEARL
                                                  ..............................
                                                  D. J. PEARL
                                                  Deputy Company Secretary