My old Gamertag is in bottom, is there anyway to remove the # name? My old Gamertag isn't...

Is there anyway I can change a name of an old account of mine and then change my main accounts name to that?

Yes. If you change the name on the old account it'll free up the gamertag for use so you can change it to that.

When I log in to Bungie, it shows my old gamertag that I signed up with, as my Bungie account name, aswell as all of my fileshare, the author is my old gamertag, which is quite annoying. But it has my gamertag next to the account name.

Does that mean that there is no way that I will be able to make available my old Gamertag name in order to change my current gamertag name? Is there no way that I can maybe delete my old Xbox Live account and with that my Gamertag? If this is possible how
do I go about in doing this.

I understand that but what I don't understand is why it didn't happen to my friend when she changed her gamertag a few hours ago - is there anyway to remove said old gamertag because when I'm in an xbox one game such as red dead online, it shows my new
gamertag like it's supposed to

On my new xbox I've redeemed my old account but I've changed the gamertag, I'm wanting to transfer games ext from my old xbox to the new one but the data is owned by my old gamertag can I still transfer from the old name to my new one ????