If you have archived an owners ledger it is possible to un-archive the ledger. 

Go to the Trust Account tab, enter ledger list and change the status of "Include archived ledgers" and search for the ledger to un-archive.

Select the ledger to un-archive, they will be highlighted in red.

Select the 'Restore Ledger' button. 

You will be prompted 'Are you sure you want to restore this ledger?', select 'Restore this Ledger' to proceed.