–    Taking guidance from Company Policy

–    In the absence of such a policy taking a second opinion from a coworker or manager.

This gives an impression that there  no  intension  on the part  of the engineer  to  hide anything.

–    In the absence of either of these options, to examine one’s own motives and use the ethical problem solving techniques.

–   One can look carefully into the professional codes of ethics which uniformly forbid conflicts of interest.  Some of these codes have very explicit statements that can help determine whether or not the situation constitutes conflict of interest.