To rename or delete pulse profiles, start by logging into your account.
In the main menu of the website where all your bits are, you'll see a 'Pulse Profiles' link - click that.
On the right of each profiles' information, there are two images. The left image allows you to rename the profile and the right image allows you to delete it.
If you are going to change or remove a pulse profile, make sure you have pulsed first. If you do not do this, all the statistics you have on your computer under this profile will not get counted on the website and you will lose them all.
If you rename or delete a pulse profile, you will not lose the statistics already counted in your account.