- disable all logshipping jobs
- restore your primary server database from backup
- restore the same database backup on to the secondary server but in the correct state (you can apply logs).
- clear out any transacton log files you have left in the designated Tlog directory or in the copy directory on the secondary server
- enable all logshipping jobs starting with the primary server.
Very straight forward, we use this in our UAT env all the time, to keep them in step.