Boutiller-86 appears to be you, and you are the profile manager. You should be able to edit anything in your profile.
It looks as though you accidentally proposed a merge of your own profile with Lake-3240. Since he is clearly not you, the merge has already been rejected, so there's no problem there.
Did you mean to propose a merge of Lake-3240 and Lake-4897? That merge was just proposed today, so you just need to approve it. If the other project manager doesn't respond, the merge will be automatically approved in 30 days, and then you can merge the two profiles.