I had a repository in SVN.
I imported it to bitbucket.
I want to reimport it and override the already created repository in bitbucket.
Can I do so?
Or have to delete and create a new destination repository ?
You can delete BB-repo, create again and re-import, while I can't see any reasons to do it.
If you want just have two repos (svn and hg(?)) in sync, better way will be to have local Mercurial repository with enabled HGSubversion extension and two paths in it: BitBucket and Subversion. With pull-push cycle you will be able to perform bidirectional synchronization easy and any time