Currently I'm using Fedora 20, but I need to replace it with Ubuntu 14.10. Can someone, please, provide step by step explanation for that?
Thanks in advance.
There is no conversion utility.
Backup the document files (including any code etc.) you have created, on to an external and/or cloud drive
Insert your Ubuntu installation media to the appropriate place on the server (optical drive/USB Port etc)
When asked if you want to keep the Fedora partition, decide if you want to keep it as a reference or wipe it out and answer accordingly. (I suggest keeping it against any "ooops" in the near future. You can remove it later)
Let the installer do its work.
Login to your system and restore your files from the beckup media
mount
anddf
on your Fedora system and add them into your original question.