Translation:By then, you will have called someone else.
Are there many occasions when para should be translated "by" instead of "for"?
I would have thought the the use of "más" would mean that you had already called someone and that you would use "otro" if not.
I'm spanish. Why is it incorrect to say: "By then, you will have called TO someone else''. Could you explain me? Thank you.
Technically, your sentence is grammatically correct. However, "to call to someone" is more like saying "to get their attention." When it's just, "to call someone," it's calling them in general, like by phone or by shouting their name.
Well since your are Spanish and having problems with it I don't feel too bad about not understanding it myself. lol
alguién más ~ someone else
alguién diferente ~ someone different
Also, you included the accent over the "e" in "alguién" which was good, but you did not use one for the "a" in "más." Here is the difference:
más ~ else
mas ~ but