[epsilonclose]

I don't know. For a sufficiently large change, it isn't necessarily in your company's best interest to try to keep you happy. You have banked knowledge and skill in X. You have limited skill in Y but wish to learn. The loss of some fraction of X is always going to hurt the company more than your gain in Y will benefit them, so they are going to try to keep you doing as much of X as possible for as long as possible. If they were to let you switch to Y, they'd have to have already needed a junior person there, and they will now have to replace the person doing X. Maybe this is a small vs large company thing, but I think it is entirely possible to "typecast" yourself into a corner such that the best thing you can do if you want to pivot is jump ship.

[caspar]

In addition to what other responders have said, another factor is that if you're a top (or better than average) performer in X, then the default assumption will be that you'll be a top (or better than average) performer in Y, given some time to ramp on Y.

That may or may not be true, of course, but it's an element in your favor either way!

(though fwiw, in my time as a past manager, I found that significant effort counted for a lot - it's cliche but folks who consistently put in extra effort and worked their butts off improved faster than those who relaxed, so they would soon exceed folks who relaxed, even if they had much less of a head start.)

[ketzo]

> it isn't necessarily in your company's best interest to try to keep you happy

This is true -- but your manager won't always act in your company's exact best interest either! I do think "management are human beings, too" is pretty important to remember.

> The loss of some fraction of X is always going to hurt the company more than your gain in Y will benefit them

I don't think you can assume this is always true. What if X is jQuery and Y is Typescript? Or X is oldLegacyCodebase and Y is newProjectInBurgeoningField?

[Falkon1313]

In some cases, probably. But in others, bringing your knowledge of X into the team that does Y can be quite valuable. Consider the case of a former product manager who knows very well what the customers need from the product, and how they use it, and now also understands the code and dev process - any dev team can really use someone like that. A subject matter expert, someone who knows the industry, designer, or whatever, can bring a lot of value to a different role.