An altercation (noun) is a change in occupation or avocation. Because it can refer to a switch in either a career or a hobby, this can be confusing. You need to consider the context to make a good guess as to which is meant. Even then, the meaning might be vague.
If you’re uncertain, it’s best to ask the speaker what he or she means. However, be careful how you phrase your question. You wouldn’t want the person to think that you are saying that he or she is conversationally incompetent. That might start a fight and it’s certainly not worth getting into a fight over it.
When talking about a change in avocation, it must be a substitution of one hobby for another. If the person does not give up the first hobby, or does not give it up expressly to free up the time and/or energy necessary to take up the new hobby, then it’s not correctly called an altercation. It’s just a new hobby.
For example, playing chess was taking up all of someone’s time and that person would, as a new hobby, rather spend all of his or her free time watching paint dry, the forfeiture of chess for paint-drying observation would be an altercation.
When talking about a change in occupation, the change has to be to a totally new line of work. For example, switching from a janitor in an office to a janitor in a school would not be an altercation. However, switching from being a janitor in an office to being a brain surgeon, would definitely be considered an altercation. Hopefully, there will be some education, training and certification involved in making that switch, but it’s not strictly necessary to fulfill the definition of altercation.