vendor name changed at the time of taking cheque printing

We have vendor in the name of BHARTH AIRTEL LIMITED. we are receiving invoice in the same number. at the time of making payment to vendor we wanted to issue cheque in the name of Airtel No: 123456. how to change the name at the time of taking cheque print. i checked up in vendor master in that alternate payee option is there but it is asking to give vendor number where as this is not separate vendor. same vendor at the time of issuing cheque we wanted to change the name alone. please give the suggestion