The phrase "wast one obligation" can be rephrased in various ways depending on the context and intended meaning. Some synonyms for "wast" could include neglected, abandoned, ignored, or overlooked. "Obligation" could be substituted with duty, responsibility, commitment, or requirement. Some alternative phrases that convey a similar idea could include "failed to meet a responsibility," "ignored a duty," or "neglected an obligation." Ultimately, the choice of words should depend on the context and desired tone, but there are many ways to rephrase the phrase "wast one obligation" in order to express the same general concept.