Yes — Royal Mail Tracked 24 Signed-For services officially require a signature upon delivery.
However, once your parcel has been dispatched by the pharmacy and is in Royal Mail’s network, you can use Royal Mail’s in-flight delivery options to make changes if needed.
Depending on availability, you may be able to:
Have the parcel delivered to a neighbour
Change the delivery day
Redirect it to your local Post Office® branch
You can manage these options using your tracking details via the Royal Mail website at:
https://www.royalmail.com/track-your-item
Or through the Royal Mail app.