This is one where the supervisor needs to know their person working for them. There need to be some more specifics as to why there is a determination this is needed? How long has the person been working in the profession and what were they doing before? What is their cultural up bringing? Are they coming from another part of the United States? Are they married or single? Do they love the job they are doing? Are they happy coming to work every day?
There are many factors that need to be brought into play before you can get responses that will be of benefit. There are some people that are introverts and they do not deal with others well and just are not social creatures. You know like you can have a doctor that is really good at what they do, but have no bedside manners.
I would say that the supervisor if it is not you, get to know the person and then go to your local apartment association and talk to them about some of their training materials.
You see I am cautious about giving a do this or that because I am one that likes to know my people and from there I know pretty much the direction I need to take in order to give assistance in whatever area!
I agree with Nate. You need to determine what goals you need this maintenance tech to achieve. If he/she is interacting with residents and handling this poorly, then there are many places to go to get training, such as Grace Hill, here on Multifamily Insiders and a host of others. But if this tech is having problems with coworkers, then there might be something else going on. It will be up to you to find out and pinpoint specific issues and address those.