Changing one or the other initially to show hesitation (6)

I believe the answer is:
dither
'show hesitation' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'changing one or the other initially' is the wordplay.
I cannot really understand how this works, but
'one' could be 'the' (both can introduce a definite example of something) and 'the' is found in the answer.
The remaining letters 'dir' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'to' acts as a link.
Can you help me to learn more?
(Other definitions for dither that I've seen before include "lather" , "Act in a nervously uncertain manner" , "Tremble - be undecided" , "Be in two minds" , "Vacillate, be indecisive" .)
