If this was a trustee to trustee transfer and it did not come through your hands you may not receive a Form 1099R. If this is the case there is nothing for you to report.
If you do get a form from either account administrator you can enter the information. The form itself may have a code G which would represent a rollover or you can answer the question about rollover. In any event, if all the funds were rolled over you will not have any taxable income from this transaction.