A throne designed for someone else (7)
I believe the answer is:
'someone else' is the definition.
(I've seen this before)
'a throne designed' is the wordplay.
'designed' indicates an anagram (designed with the letters).
'throne' is an anagram of 'nother'.
'for' is the link.
(Other definitions for another that I've seen before include "On earth (anag.)" , "encore?" , "Additional: alternative" , "A further (item)" , "second" .)