Final answer:
For a stage I pressure ulcer on the greater trochanter, the nurse should instruct the client to regularly shift weight while sitting to relieve pressure and promote blood flow to the area.
Step-by-step explanation:
A home health nurse instructing a client with a stage I pressure ulcer on the greater trochanter should emphasize the importance of reducing pressure on the affected area to promote healing. Hence, the most appropriate advice would be for the client to shift weight every 15 minutes while sitting. This practice helps to alleviate the constant pressure on the ulcerated area, enhancing blood flow and preventing further tissue damage. While changing the dressing daily might be necessary in some cases, it is not the primary prevention strategy for pressure ulcers at stage I. Applying a heating pad is generally not recommended as it could increase the risk of burns or further injury, and massaging the ulcer may also cause additional harm and is not advised.