there is a contract renewal module for software verticals, which is technically not a CLM ((contract Lifecycle Management). You can integrate most of CLM- docusignCLM (springCM), Adobe Esign/contract, Pandadocs etc. For your test case would be to use custom field and records to hold contract data in netsuite. With custom record and custom fields in transactions would be able to track your contractual details. I would use a custom record to hold tall the contract data and make it a child of the entity(vendor/customer) this will allow you to manipulate data efficiently.