In my experience the 18 months 'rule' is much more a guideline than a hard rule. I've personally seen a number of cases where someone transferred much sooner than that for a variety of reasons.
If you approach situations like this in a constructive and professional manner, the company will go to great lengths to find a solution. At least that's been my experience.
If you approach situations like this in a constructive and professional manner, the company will go to great lengths to find a solution. At least that's been my experience.