[R] Renamig a factor

[Agustin Lobo]

Which is the proper way to rename a factor?
If I do:
test$Parc[test$Parc=="OlÞrdola"]<-"Olèrdola"
R complains that
Warning message:
invalid factor level, NAs generated in: `[<-.factor`(`*tmp*`, test$Parc 
== "OlÞrdola", value = "Olèrdola")

Thanks
Agus
-- 
Dr. Agustin Lobo
Institut de Ciencies de la Terra "Jaume Almera" (CSIC)
LLuis Sole Sabaris s/n
08028 Barcelona
Spain
Tel. 34 934095410
Fax. 34 934110012
email: Agustin.Lobo at ija.csic.es
http://www.ija.csic.es/gt/obster