Make last call on way public (6,3)

I believe the answer is:

string out

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'make' is the definition.
Although both the answer and definition are verbs in their base form, I don't understand how one could define the other.

'last call on way public' is the wordplay.
'last call' becomes 'ring' (synonyms. I am not sure about the 'last' bit.).
'on' says to put letters next to each other.
'way' becomes 'st' (abbreviation for street).
'public' becomes 'out' (I've seen this before).
'ring' after 'st' is 'string'.
'string'+'out'='STRING OUT'

Can you help me to learn more?

(Other definitions for string out that I've seen before include "Extend" , "Prolong" .)

I've seen this clue in The Telegraph.

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