Locate the file

The player data for Server Utilities is located in the world/save folder.
If it is single player:
– [dir]/saves/[save file]/playerdata/
If it is multi-player:
– [dir]/[world]/playerdata/

Inside the playerdata folder you will need to find the data you want to edit. The file names are the player’s UUID. You can find the UUID for any player using their username HERE.
When you have the UUID you need to look for the .pdat file extension or PDAT file type. Do not use the .dat or DAT. Those are Minecraft’s data files.
Next, open the [uuid].pdat file in a text editor of your choice.

Editing Ranks

Inside of the PDAT file you will find a lot of info. You want to look for where it says: “ranks”. It will have a list of all the ranks that player has.

If you are simply wanting to change the rank, select the name of the rank in the quotes and replace it with the desired rank.

If you are wanting to add a rank then after the last rank add a comma and a set of quotes. Add the name of the rank inside those quotes.

If you are wanting to remove a rank then select the quotes and the comma after the previous rank and delete them. The player MUST have at least one rank.

After you are done editing the ranks, save the file and restart the server. Your changes should be applied after the restart.