ae3o Short version - no.
Long version - I assume you use the whatever translator is built into it. It has a txt file it drops whatever it translates into so that if the same** text comes up again, the translation can be read from there instead of having to send a request to online translator again. You can open that file, find the character names**, change the recorded translation and save that file.
**The caveat, and the reason the short answer is "no", is that the translator grabs the whole block of text rather than splitting it into separate words. For example, even if you change MC name to Kuro using the method I mentioned above, if her name comes up as part of a sentence (e.g., someone addressing her by name), you are still going to see "Blackout" or whatever it gets translated as; it will only show up as "Kuro" whenever it is the only word in the sentence (e.g., part of the message window that shows which character is talking right now). In other words, it is a bandaid fix at best, and only works on text you have already seen [and stored in that TXT file].