Some FSDO appointments are still going ahead, via Zoom! Don't know if this includes 61.75 issue, but I believe they will do address change and license number change. Obviously getting the Temporary Certificate is a problem this way, but they have an web/email facility, once the document is processed in Oklahoma.
On a related matter, once issued, you need to complete a Flight Review (aka Biennial) before acting as PIC, and an IPC before exercising your IFR privileges (if issued).
Having completed an IPC, remember to log your Instrument Approaches 6 in 6/12 months, so you never need another IPC. These can be conducted in an AATD, such as Redbird.