I can not find any reference to this being a possibility.
Is it possible in SalesForce to have an Approval process time out and a reminder (they don't approve it or approve it within few days) cause a reminder email to be sent to those that approval is being waited upon from? Also is it possible to Lock the whole opportunity including Notes & Attachments(So nobody can add any notes or attachments after submitting for Approval)
is_in_approval_process__c
(boolean) andentered_approval_process_date__c
. Then you can use normal time-based workflows to send email alerts. When the record leaves the approval process, reset both fields to false/null. Email will need to go to an email field on the record being approved. Multi-step approval processes would require a scheduled apex job – cropredy Feb 19 '15 at 1:05