How to delete password or change user login name for Subclipse

I got a new user to use when logging in to a Subversion (SVN) repository. I use "Subclipse", a Eclipse SVN plugin. I had added a SVN repository with my old user:

Unfortunately there is no GUI to change username or password. The usernames and passwords are stored in a SVN client implementation specific way. If you use SVNKit:

the passwords are stored in the Eclipse keystring (along with many other password-alike things). If you delete this file (configuration/org.eclipse.core.runtime/.keyring) and restart Eclipse then you will be prompted to enter username and password again. Note: while deleting this file you will delete other things stored by other Eclipse plugins!