During plan execution, a lot can fail! Below is a list of working plan repair approached. Please be aware that they might implement different semantics, in particular with regard to the HTN solution criteria. Keep in mind that plans are only regarded as such in HTN planning if they can be obtained from the initial task network. When plans fail, this requirement might be too strict: Some approaches still demand this, others not.
IPyHOP, a reentrant version of GTPyho
Plan Repair via Encoding into HTN Planning:
Stable Plan Repair