Were you represented by an attorney when you made this agreement? How long ago was the agreement made? You can always petition for modification. Modification of the parenting time arrangements can be made based upon what is in the children's best interest. Modification of the custody award is much more difficult as a substantial change in circumstance must be shown.
I don't practice in OR but this sounds like a case where modification may be warranted. However, what you might need to ask for is an order appointing a therapeutic interventionist-this is someone with psychology experience who will be able to assess what is happening here with the children and hopefully deal with the source of the problem. If it's alienation, disparaging of you or the like, he or she should be able to assist in identifying it by working with and interviewing the children. The goal is not to point fingers; the goal is to identify the problem and fix it so you can enjoy the remainder of your children's youth with them.
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