Vacant space filled by tour band (6)
I believe the answer is:
stripe
'band' is the definition.
('stripe' can be a synonym of 'band')
'vacant space filled by tour' is the wordplay.
'vacant' suggests removing the centre.
'filled by' indicates putting letters inside.
'tour' becomes 'trip' (I've seen this in other clues).
'space' with its centre taken out is 'se'.
'se' enclosing 'trip' is 'STRIPE'.
(Other definitions for stripe that I've seen before include "bar" , "Narrow band of colour" , "Band of contrasting colour" , "Chevron on a uniform to denote military rank" , "Streak" .)