Canon 67

Can. 67 §1. If it happens that two contrary rescripts are obtained for one and the same thing, the particular prevails over the general in those matters which are particularly expressed.

Can. 67 §2. If they are equally particular or equally general, the earlier in time prevails over the later unless there is express mention of the earlier one in the later one or unless the person who obtained the earlier one has not used the rescript out of malice or notable negligence.

Can. 67 §3. In a case of doubt whether a rescript is invalid or not, recourse is to be made to the one who issued it.