How to find a previous stake president's MRN?

We just called a new bishop who was ordained bishop before by previous stake president who is no longer in our stake anymore and new bishop doesn't have ordination record but only dates.

I know former stake president's name because I found him through cdol. But I still cannot register new bishop in LCR because I don't know former stake president's MRN.
This case what should I do with this?

You may need to call the GSD for assistance on this. They have the resources necessary to help with what you are trying to do. No one here has access to the information you need. The GSD support people most likely won't give you the MRN but they most likely can work out a solution, or at least put you in contact with someone who can help if they cannot help.

The problem is that his bishop ordination doesn't have that person recorded on it otherwise it would already show when you add him as bishop. As jdlessley said work with the GSD and they can update that thru the old CDOL still. Once they do that you will see it show up in LCR as you try to record him as the bishop.