How do you Un-Expire an item instance?

We have situations with multiple item instance expired unintentionally and as a result all subsequent transactions are stuck in pending status. Has anyone ran into this situation? If so, how do you Un-Expire an item instance. From what I understand, one way to do this is to use the open interface, meaning populate records in the interface table with appropriate attributes and push them through running the open interface program thereby effectively updating the instance. Has any one done this? if so can you provide the detail instructions/sql to insert records into the interface table?
Any information to this respect is highly appreciated.