Hi @OlympusMons ,
Agree with what Andy said. You could export the resource mailbox to .pst file. Then import the .pst file to new resource mailbox.
Accoridng to my test. Grant the "Full Access" permission of the resource mailbox to another mailbox. Then login to resource mailbox in outlook client, then click File -> Open&Export -> Import/Export -> Export to a file. Then grant the “Full Access” permissions of the new resource mailbox to another mailbox. Log in to the new resource mailbox. And use the above steps, and finally select "Import from another program or file" to import the .pst file. As Andy said, migration may cause some information to be lost. Please ensure that the calendar information is complete before deleting the previous resource mailbox.
For more information you could refer to: How to import and export calendar in resource mailbox?
The following screenshots is the test in my lab environmennt, I export the Room2 mailbox to .pst file and import the .pst file to EXORoom3 mailbox. We can see that the calendar information in Room2 appears in EXORoom3.
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