When you have made a mistake the most effective approach is always to acknowledge the error without reservation.  This can include explanations, rationale, apologies, offer for recompense, but most important is clear communication relative to acceptance of the fault. 

This clear statement of fault equates to the ancient Japanese tradition of falling on your sword to account for misdeeds (a bit drastic an approach, but okay as an exaggerated analogy).

Clarity and Sincerity

Non apologies are rampant in our culture.  These lead to the question “Do you really mean it”.  If you want to get past the error and move on, the others must believe you accept fault.  

Accepting fault, and making it clear you are fully accountable for you actions provide a solid foundation to resolve the issue.  This does not mean (although often recommended) you need to apologize but you do need to admit complacency. 

Although it does sound trite, problems are a great opportunity to build solid longterm sustainable relationships with others.  The key is how you deal with the issue.  Clear acknowledgment an issue has occured is always the first step. 

Taking Action

Once it has been established an error has occurred and accountability communicated, what next?  Resolving the issue to the satisfaction of all.

You may not be responsible, i.e.,  caused the problem,  but accountability is simply agreement a problem occurred and defining who (you) will resolve it.

Resolution actions can vary widely.  The key here is to achieve an outcome that all the involved stakeholders concur solves the issue.