Al has left one country for another (7)
I believe the answer is:
austria
'for another' is the definition.
I can't tell whether this definition defines the answer.
'al has left one country' is the wordplay.
'has left' indicates named letters should be taken away.
'one country' becomes 'Australia' (Australia is an example).
'australia' with 'al' taken away is 'AUSTRIA'.
Can you help me to learn more?
(Other definitions for austria that I've seen before include "Original setting for Mozart" , "EU member" , "Mountainous European state" , "European nation" , "The capital is Vienna (7)" .)