To be next to Joan, I'd moved (6)
I believe the answer is:
adjoin
'to be next to' is the definition.
(I've seen this before)
'joan i'd moved' is the wordplay.
'moved' indicates anagramming the letters.
'joan'+'id'='joanid'
'joanid' anagrammed gives 'ADJOIN'.
(Other definitions for adjoin that I've seen before include "Interconnect" , "Lie next to" , "Be next to (something)" , "Of building, be situated next to" , "Neighbour" .)