Reincarnate will likely only see use if making a new character at the current level is not an option. There is no point to a random race when you can pick one (or just carbon copy the original character). Reincarnation is spiritual remnant of a harder time when you had to take any resurrection option available to you.
That said if your concept is so inflexible it can't survive a minor thing like an in-game justified race shift, you may need to look at it again (character freak-out may be justified).
The big question that may throw things out of whack is if you are allowed to use race-based feats and/or classes. If yes, then no problem (you either learned the techniques already or maybe your souls is strengthened by your experience, whatever), if no, I would absolutely expect a refund of the resources used as well as a brief window to respec the character a little based on his newfound attributes.
That said if your concept is so inflexible it can't survive a minor thing like an in-game justified race shift, you may need to look at it again (character freak-out may be justified).
The big question that may throw things out of whack is if you are allowed to use race-based feats and/or classes. If yes, then no problem (you either learned the techniques already or maybe your souls is strengthened by your experience, whatever), if no, I would absolutely expect a refund of the resources used as well as a brief window to respec the character a little based on his newfound attributes.