Although I cannot find the abbreviation "PP", I am quite sure that it stands for "passaggi posturali" here, as this skill is often mention together with "trasferimenti". Also, a physical evaluation of a patient includes his/her ability to perform ADL, postural changes and transfer him-/herself from sitting to standing, from a wheel-chair to bed, to walk etc. A non independent patient usually needs the personnal to help him/her with his/her position changes (turning to the sides in bed, from side lying to supine etc.), in transferring him/her and in performing various ADL activities, such as getting dressed etc. I am not equally sure of the English expression, but "position changes" is be used and does explain the meaning.

Please, see ref.1: "Care should be taken in making position changes slowly because orthostatic hypotension could occur." https://books.google.se/books?id=cAwlCwAAQBAJ&pg=PA2130&lpg=...

Ref. 2: "Patient is unable to operate bed for position changes independently." https://books.google.se/books?id=E6ddrJjtz4oC&pg=PA289&lpg=P...

Ref 3.: The Braden Scale: "No imitations, makes major and frequent body position changes without assistance. https://books.google.se/books?id=QlMiCgAAQBAJ&pg=PA274&lpg=P...