Modify 2008 Divorce Decree - income tax purposes

I wish to modify my North Carolina 2008 Divorce Decree in regards to noncustodial parent’s ability to claim oldest child (now 16) for income tax purposes. The decree does not have any conditions that the noncustiodial parent must meet in order to claim. However, the noncustodial parent has not met his obilgations in regards to visitations and therefore I believe he should not be entitled to that privilege. Yes this is about money but it also takes more than money to raise children and time spent with them is a big part of that. He does not even come close to housing or for that much even seeing either of the children during the year to be entitled to that privilege.

The decree states the following in regards to taxes:
The Husband shall hereafter be entilted to the dependency exemption for income tax purposes for the parties’ oldest child and the Wife shall hereafter be entittled to the dependency exemption for income tax purposes for the parties’ youngest child. Husband and or Wife shall make or execute any election statement or other document required to give effect to this covenant.

IRS states that, if a divorce decree or separation agreement went into effect after 1984 and before 2009, the noncustodial parent may be able to attach certain pages from the decree or agreement instead of using Form 8332. The decree or ageement must state all three of the following.
1)The noncustodial parent can claim the child as a dependent without regard to any condition such as pay of support. (no problems with child support-wages are garnished)
2) The custodial parent will not claim the child as a dependent for the year.
3) The years for which the noncustodial parent, rather than the custodial parent, can claim the child as a dependent.

What would I need to do to have this decree modified?
Can I do it on my own?
Lastly, is it worth changing?

You would have to file a motion to modify the Order, and based on these facts, I do not believe it would be successful.

What information/situation would be needed for it to be successful?

In order to change a custody/support order you must show that a substantial change in circumstances which affects the wellbeing of the child has occurred. Though the lack of visitation certainly affects the children, its relation to the dependency exemption does not.