Selva,
I think reguh-zname1 will not get the name from LFA1 but from the Invoice.Whatever the name that was available in the vendor master at the time of creating of Invoice will carry forward to the Payment run.Loooooooooooooong back we discussed this issue regarding the Vendor Name that is getting printed and I think that is what the conclusion of the discussion with FC and SME.Let's await a concrete reply from experts.
Did you checked other Name fields related to the Vendor in Reguh on whether they are matching with the name that was changed ?
K.Kiran.