An example would be smoke signal seen over reservation originally (4)
I believe the answer is:
cure
'an example would be smoke signal' is the definition.
I can't tell whether this defines the answer.
'seen over reservation originally' is the wordplay.
'seen' becomes 'cue' (I can't justify this - if you can you should believe this answer much more).
'over' is an insertion indicator.
'originally' suggests taking the first letters.
The first letter of 'reservation' is 'r'.
'cue' placed around 'r' is 'CURE'.
Can you help me to learn more?
(Other definitions for cure that I've seen before include "Make well again" , "Preserve by smoking - make better" , "Heal or pickle" , "Restore to health or preserve with salt" , "Treat - French parish priest" .)