You'll want to look in Scripts/Misc/Notoriety.cs
This one is for BaseVendor.
https://github.com/ServUO/ServUO/blob/493fde408ae48752bcd2bb899d2a2e42055b22c7/Scripts/Misc/Notoriety.cs#L292
Change line 293 to Return Notoriety.Innocent
If you use the Felucca ruleset then they are attackable but...
https://github.com/ClassicUO/ClassicUO/blob/8ff33a50c46dafbbb7ed55109ab927bb520813de/src/ClassicUO.Assets/ProfessionLoader.cs#L122
This should do the trick:
/*Professions[new ProfessionInfo
{
Name = "Advanced",
Localization =...
Sorry my memory is rusty. If you know who the playermobile is then try
[global interface where playermobile name = WhateverthePlayerNameIs
Pull them to you fix what you need then if the character is offline
[set map internal