1. Open Windows Explorer.
2. Right-click anywhere in the window.
3. Click TortoiseSVN → Settings.
4. Click Saved Data.
5. Click Clear beside Authentication Data (see below).
6. Check the authentication items to clear.
7. Click OK.
All saved Authentication Data for all projects is deleted.
You will have to re-enter credentials to reconnect.
参考链接：https://stackoverflow.com/questions/1153489/how-to-change-users-in-tortoisesvn