The part III revoke section is only used if you previously signed part II releasing the depending for future years. If you did, then part III does not take effect until the year after the 8332 part III is filed.
If you furnish a new 8332 form with part I each year then you simply give the non-custodial parent the 8332 part I form only for the year that you are releasing - if you are not releasing then you simply do not provide the form.
Because of the year delay for part III to take effect, it is a bad idea to sign an open ended release part II because circumstances can change. You have better control by only using part I each year that the ex claims.
@macuser_22 @@ I didn't realize how messy my question was. So I would fill out part 2 with all the odd number years he can claim? Or just for 2021
2021?
If you did not already provide a 8332 with part II filled out, then if you are letting him claim for the 2020 tax year (filed in 2021), you just provide a 8332 form with part I filled out which will release for the 2020 tax year only.
If you want to use part II to release in future years then per the 8332 instructions:
Part I. Complete Part I to release a claim to exemption for your child for the current tax year.
Part II. Complete Part II to release a claim to exemption for your child for one or more future years. Write the specific future year(s) or “all future years” in the space provided in Part II.
To help ensure future support, you may not want to release your claim to the exemption for the child for future years.
If every other year you can also specify "all future even tax years" (or "odd" tax years as the case may be).