Call six to be seated (5)
I believe the answer is:
visit
'call' is the definition.
(I know that call can be written as visit)
'six to be seated' is the wordplay.
'six' becomes 'VI' (Roman numerals).
'to be seated' becomes 'sit' (I've seen this before).
'vi'+'sit'='VISIT'
(Other definitions for visit that I've seen before include "Drop in; frequent" , "Come to see" , "See; temporary stay" , "Call upon" , "Pay social call" .)