Trying to modify an .eps file exported from sigmaplot and text is not embedded. Is there a way to embed in Ai or does it have to happen in sigmaplot?

Hi all.

First time posting. I have 9+ graphs that are exported from sigma plot as .eps files. I am trying to modify all of them in Ai to conform to a scientific journals style rules. It seems that the .eps files do not have text embedded and so all of the words and numbers come out as vectors and therefore cannot be easily modified in Ai. I tried using the pdf files exported from sigmaplot and for whatever reason ai did not let me modify these at all. My question is, is there an easy way (post export from sigmaplot) to get ai to recognize the text as text? Or, is this something that has to be done in sigmaplot before exporting?

Much appreciated.