Use Scott's Tagging Tools plugin. By putting a line "aliasname,tagname" into the textbox in the plugin options you create an alias for a tag. By putting just a tagname (without alias) into the same textbox you remove the tag.
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask here, in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.