An unconditional waiver for partial payment is used to retain proof that a subcontractor (claimant) was paid for their work up to a specific day and month to ensure a lien cannot be filed. By signing their name, the contractor releases their right to file a lien on the property for the amount they were paid (as stated on the waiver).
An unconditional waiver for partial payment, in contrast to the unconditional waiver for final payment, applies to laborers who still have work to complete on the property. Unlike conditional lien waivers, unconditional waivers are used after payment has been provided to the claimant. Using waivers is highly recommended due to the level of financial security they provide to the party making payments (typically general contractor or owner).