It's the other way around

If a transguy takes too much testosterone, his body will start creating loads of estrogen.
Which is why ftms should never take more t than prescribed. It'd amount to nothing, except increasing his estrogen levels.
I have no idea if it does the same for a transgirl (too much estrogen, body counter attacks with more t.)
But no, hormones can't magically become something else.
Just like fat doesn't become muscles or the other way around.