The phrase "head at pass" can be a bit tricky to find synonyms for, as it is a relatively specific term. However, there are a few possible options. One synonym for "head" could be "lead," as in the lead person or animal in a group. Another option might be "front," which could refer to the person or object at the front of a line or formation. As for "pass," synonyms could include "checkpoint," "gateway," or "portal." Keep in mind that the phrase "head at pass" may have a particular meaning or context depending on the situation, so it's important to consider that as well when looking for synonyms.