In an online environment, an E-Procurement process should be able to react and adapt in near real-time to changes in suppliers, requirements, and regulations. WS-BPEL is an emerging standard for process automation, but is oriented towards design-time binding of services. This missing issue can be resolved through designing an extension to WS-BPEL to support automation of flexible e-Procurement processes. Our proposed framework will support dynamic acquisition of procurement services from different suppliers dealing with changing procurement requirements. The proposed framework is illustrated by applying it to health care where different health insurance providers could be involved to procure the medication for patients.