utm parameters – How can I merge historical source/campaign/medium in Google Analytics?

I typically direct traffic to the sites I work on with heavy use of UTMs for later analysis, eg:

domain.com/some_page?utm_source=eblast&utm_campaign=january_campaign...etc

Unfortunately the one I’m working on now has a whole list of different spelling variations – Email, eBlast, Eblast etc. How can I merge these in Google Analytics? They should all be the same entry

how to merge these