Make uniform and flag one - synchronise edges (11)
I believe the answer is:
standardise
'make uniform' is the definition.
('make uniform'->'standardize' is in my internal thesaurus and 'ize'->'ise')
'flag one synchronise edges' is the wordplay.
'flag' becomes 'standard' (standard is a kind of flag).
'one' becomes 'I' (Roman numeral).
'edges' suggests removing the centre (I've seen 'edges of' mean this).
'synchronise' with its centre removed is 'se'.
'standard'+'i'+'se'='STANDARDISE'
'and' acts as a link.
(Another definition for standardise that I've seen is " Idea strands? (anag)".)