The Maharit (1:127) has a discussion whether one can make a shliach to be makdish something, because the hekdesh is achieved through speech and should be a problem of mili lo mimsaran l'shliach. The Nodeh B'yehuda (tinyana, Y.D. 147 - written by his son) writes that the issue of the maharit seems completely unconnected with the concept of mili lo mimsaran l'shliach (mlm"l). The concept of mlm"l means that a shliach who is told to do something with words such as told to write a gett, cannot give over that shlichus to a second shliach because all he is giving over to the second shliach is the command to write the gett [nothing but words]. This is apparent from Rashi on 66b and from Rashi on 29a d.h. rava - שלא מסר להם אלא דברים ואין בדברים כח להיות חוזרים ונמסרים לאחר
But one is perfectly able to set up a shliach to do something that only involves speech such as be makdish something for him, and this in no way violates mlm"l. The issue would only be when Reuven would appoint Shimon a shliach to be makdish something for him, whether shimon can now go and appoint levi to do it - based on mlm"l shimon doesn't have the ability to give over mere words to a second shliach.
However, R' Shlomo Vilna points out that Rashi on 71b seems to hold that any shliach who is appointed to just do says words to someone. Based on this rashi it would be plausible that one cannot set up a shliach to be makdish something because of mlm"l. To deal with the contradiction in Rashi to explain the nature of mlm"l, R' Shlomo Vilna suggests that it depends whether we are allowing "omer imru" - meaning whether reuven telling shimon to tell levi would work. According to the approach of mlm"l, but omer imru would work, it must be that words can in fact be given over to the first shliach, just that the first shliach is unable to appoint a second shliach (as rashi says on 29a and 66b). But according to the approach that "omer imru" doesn't work either, it is possible that the problem is that a shliach can only be appointed to do an action but can never be appointed to just say something.
The Nodeh b'yehuda asks 2 questions on the maharit, who doesn't allow a shliach to be makdish something. 1. It is omer imru, and even though all hold mlm"l, some to hold that omer imru works. 2. The maharit understands that mlm"l means one cannot appoint a shliach to say something, which is against Rashi on 29a and 66b. Based on R' Shlomo Vilna that the definition of mlm"l is completely dependent on whether we accept omer imru, and if we would accept omer imru then the maharit's understanding is correct - both questions of the nodeh b'yehuda are really one - since some pasken omer imru therefore one should be able to be makdish through a shliach (but if we would pasken that omer imru doesn't work, then being makdish through a shliach would in fact be a violation of mlm"l).