Algorithm suggestion for ticket routing system using Machine Learning
Linear regression does not seem like the right tool here.  This isn't a regression problem; it is a classification problem.  Regression outputs a continuous number; you need to output a category (which place the ticket should be routed to; presumably there is a finite list of candidate places).

I would suggest that you learn about natural language processing.  The very simplest thing you could try would be naive Bayes with bag-of-words features.  Fair warning: I would not expect that you will get especially good results without a lot of knowledge of NLP (and maybe not even then); it's probably going to be challenging to find a good solution for your problem.