Sometimes the quickest way out of something is straight through it. This advice holds true in life, and in trademarks.
Those who deal with trademarks are familiar with obstacles to registration based on similar third-party marks. It’s frustrating, and especially so if you had conducted a clearance search beforehand in an effort to avoid such obstacles and see no reasonable basis for the Trademark Office’s refusal. Other times, the Trademark Office may approve your application for publication, but a third party will oppose registration during the opposition period. Or maybe you haven’t even applied for registration in the Trademark Office, but you receive a letter threatening legal action if you do not cease and desist from the use of your mark.