split duration when changing time signature

[Stjepan Horvat]

is there a way to split duration of long notes when chaning time signature:

\time 4/4
c1

to

\time 2/4
c2 ~ c2

i'm intrested in the output?

-- 
Nesmotren govori kao da mačem probada, a jezik je mudrih iscjeljenje.
Izreke 12:18