Can vows to God be change,broken or stop

Todays time in which christian live ,entrapment is possible because the world knows the people of faith tell the truth and keep promises. Can you as a honest  person make a vow to God and next month or days you decide to change your vow.Not because you wanted to trick God but because he took care of the problem or  worrys you had ,whatever it was you went to him and now it is solve.Should you finish or complete your part of the vow .