When a pledge to God is made, could it be changed even by a church authority? Does an absolution from a pledge by a priest stand right in the sight of God, or not?
The priest can release a person from his vow if it was a wrong vow like that of Jephthah (Judges 11:30) for example, or if the vow is not practical or not within a personís ability to maintain. For example, vowing to baptize a son in Jerusalem, or vowing to make a son a monk. The most important point is that this release should be based on Biblical background not just emotion.
In the Holy Book of Leviticus chapter 27, God designated laws to be followed when someone made a vow and was unable or did not want to keep it. "But if he is too poor to pay your valuation, then he shall present himself before the priest, and the priest shall set a value for him; according to the ability of him who vowed, the priest shall value him" (Leviticus 27:8). The priest role is not to release him totally from his vow but to set for him a value that is feasible according to his circumstances.