My employer (company B) is a consulting firm that provides subcontractors like myself to other companies in the aerospace and automotive sectors. I have been already two years in this company and have been considering taking a 4 month sabbatical for over a year now.
One of my complaints so far had been the short duration of the projects. Finally, a few months ago they assigned me to a new project for company A with a longer duration than previous ones: around a year. This would be great had it come much earlier, but at this moment all I want is to leave the company, have 3-4 months to devote to my family, friends, personal projects and (dare I say it) my own enjoyment. After that I plan on going back to work for a company other than B, as their remuneration is too low.
So I'm in the middle of the project, which upon completion would involve training employees from company B with the knowledge acquired from company A, with no motivation or intention to stay any longer. I have decided to hand in my resignation letter. Staying for a longer time is not something I'm considering.
The question is:
How can I do this without burning bridges and minimising damage to my relationship with company A?
I am not as concerned about my employer (company B) although I understand any advice will likely apply to both.