Give the water treatment (6)

I believe the answer is:

aerate

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'give' is the definition.
The definition and answer can be both related to change as well as being verbs in their base form.
Maybe they are linked in a way I don't understand?

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for aerate that I've seen before include "Introduce air into" , "Introduce gas to" , "Charge with a gas" , "Fill with bubbly gas" , "Turn from still to sparkling" .)

I've seen this clue in the Evening Standard.

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