rolling over the errpt file

Good Morning,
This morning I was asked to decrease the size of /var/adm/ras/errlog file.
So I ran the errclear command but this does not shrink the file size.

Question:

Is there a way to a binary extract of the errlog log and only keep the last
90 days? Maybe a script to roll the errlog every 30 days?

Thanks
Vince