According to Wikipedia, Geneviève Bujold wanted Voyager's Janeway's first name to be changed from Elizabeth to Nicole. Later, Kate Mulgrew requested the name to be changed again to Kathryn. Why did both of these actresses request the name changes?
Legal tip-toeing, Genevieve's preference, and then preference by the producers(?). 'Kathryn' was chosen before Kate joined the cast.
Jeri Taylor, co-creator of Star Trek: Voyager:
Caveat, the above is a quote in an interview that I am still trying to locate from Cinefantastique. I have emailed them, but I will edit this if someone finds it first. This should do, but more direct is better.
I have a suspicion it was due to Picard. More specifically, that he was French with a British accent!
Then the reverse became true when Kate Mulgrew was re-cast into the role. While I can't say her state of mind for certain, she may well have wanted to veer away from a French name. So why not choose her own?