If you removed enough fluid to bring the level down to normal, that should be all that is required.
The question is, what type of fluid did they put in? This transmission requires a special Honda-matic fluid that is generally only available at the Honda dealer. if someone filled it with regular Dexron/ Mercon fluid, this can cause damage to the friction materials inside the transmission.
I would suggest taking the vehicle in to your local Honda dealer to have the fluid changed (or an independent shop that specifies that they will install the original, correct Honda fluid with their service). This way, you can rest easy knowing that the transmission is filled with the correct amount of the correct fluid type.
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