Steps to take prior to moving someone to "address unknown"

Is there a list of steps that I should take to try to find someone's new address? If so, where do I find that? Currently, we just send an envelope marked "Address correction requested" to the address we have on file.

See the first paragraph in the help center article Move Records Out.

Notice that the envelopes you have with the bishop's name and address printed on them use the instruction: RETURN SERVICE REQUESTED.

In addition to the article in the Help Center, the steps are also shown in LCR any time you attempt to move record(s) out with no known address.