Deleting pushed merge and commit from original repository and commit history on GitHub

Question:
I have to delete 2 last commits pushed to original repo, one of which is a merge commit. I want to delete changes in repo and keep them on my computer.
When I do

        git revert -m 1  075cc2f 
It adds a revert commit to my history of commits and my 075cc2f commit is still present there. 
When I do

        git push origin +HEAD^:master
commit is fully deleted from history.
However, when things come to merged second commit, it is being deleted only with commits of a person who pushed before me. We both had some version "v" at moment of cloning a repo. He pushed his commit to original repo and version of a project became  "v+1". I still had version "v" and merged a project by:

        ➜git add .
        ➜git commit -am "My commit»
        ➜git pull  
        subl -w: subl: command not found
        error: There was a problem with the editor 'subl -w'.
        Not committing merge; use 'git commit' to complete the merge.
        ➜git commit -am "My commit»
        ➜git pull  
        Already up-to-date.
        ➜git push -u origin master

When I use to a merged commit:

        git push origin +HEAD^:master
It is being deleted only with commits of a person who pushed before me.
Now I want to delete that merge commit from history fully without deleting other people's pushes.


[There is another way to do this][1]

> You could follow these steps to revert the incorrect commit(s) or to reset your remote branch back to correct HEAD/state.

>  1. checkout the remote branch to local repo.<br/>
> `git checkout development`
>  2. copy the commit hash (i.e. id of the commit immediately before the wrong commit) from git log
>  `git log -n5`
> > output: <br/>
> > 
> commit 7cd42475d6f95f5896b6f02e902efab0b70e8038 "Merge branch 'wrong-> > > commit' into 'development'" <br/>
> commit f9a734f8f44b0b37ccea769b9a2fd774c0f0c012 "this is a wrong commit" > <br/>
> commit 3779ab50e72908da92d2cfcd72256d7a09f446ba "this is the correct > > > commit"
> 
>  3. reset the branch to the commit hash copied in the previous step <br/>
> `git reset <commit-hash> (i.e. 3779ab50e72908da92d2cfcd72256d7a09f446ba)`
>  4. run the `git status` to show all the changes that were part of the > > wrong commit.
>  5. simply run `git reset --hard` to revert all those changes.
>  6. force-push your local branch to remote and notice that your commit > > history is clean as it was before it got polluted.<br/>
> `git push -f origin development`

[process][2]

But again it deletes not only merged commit, but also his parent

[before][3]
[after][4]


           commit b142e1ed9 has 2 parents f4cc23a + 2537c51 


  [1]: https://i.stack.imgur.com/G4T7O.png
  [2]: https://i.stack.imgur.com/3lYvR.png
  [3]: https://i.stack.imgur.com/wJHyJ.png
  [4]: https://i.stack.imgur.com/kmpin.png
  
  
  
  Solution:
  The question is solved after some practice, so here is summary what I got so far.
1. Back up original files somewhere since things we gonna use will rewrite the history.
2. Visualize commit structure of the project.

    merged
    ^   ^
  /       \
mycommit   his commit 2
  ^         ^
  |         |
repo -->   his commit 1

3. Select a fork from which select a commit on which top you will reapply all commits. Thus, all changes  after fork was created will reapply like inline process and not a merge.
4. Use  git rebase -i -m <specific commit> // in my case it was <another person’s last commit>
5.  git push -u origin master --force
6.  Check on github, whether you correctly unmerged a fork. If failed, upload previous version  from backup folder using git push -u origin master --force. 
    
mycommit   
  ^      
  |  
his commit 2
  ^
  | 
his commit 1
  ^
  |  
 repo  




1. Previous step did an unmerge. If you still have your commit, but inline and still want to delete it from history. You can do git push origin +HEAD^:master. This will rewrite history one step back from last on push. Consecutively git push origin +HEAD:master will undo rewrite on push. git push origin +HEAD^^:master will rewrite history two  steps back from last on push. git push origin +HEAD:master will undo rewrite. 
2.  However, if you did this changes to a project and want to save them: clone repo in new folder and push only from new clones. Since if you will make git push origin -u master  after git push origin +HEAD^:master this will undo your rewrite since git push origin +HEAD^:master does not change commits inside your computer (logs, history), but only on a push writes everything like last commits does not exits. But they do not stop to exist in your folder on computer.

his commit 2
  ^
  | 
his commit 1
  ^
  |  
 repo  
 
 Overall:
git rebase -i -m <another person’s last commit>
git push -u origin master --force
git push origin +HEAD^:master