Conditions necessary for a conflict of interest:

1. the person must be in a role
2. the person must be in a position of trust
3. the person must have the power or authority to make decisions
4. the decisions must be ones that need to be made on the basis of certain criteria

X has a conflict of interest if the conditions above (1 - 4) are met and X has other interests that might tempt a (normal) person to make positional decisions on the basis of those interests instead of on the basis of the appropriate criteria.