I call in before ends of lines (7)
I believe the answer is:
termini
'ends of lines' is the definition.
(I've seen this before)
'i call in before' is the wordplay.
'call' becomes 'term' (terming is a kind of calling).
'before' means one lot of letters go next to another.
'term'+'in'='termin'
'i' put after 'termin' is 'TERMINI'.
(Other definitions for termini that I've seen before include "limits of service" , "Stops" , "Some like Victoria" , "Rail stations mainly in city centres" , "End-points" .)