If using "rent" or "lend" can be confusing, maybe you could use "commission."

I consider that the expression "delegate" is the most appropriate, but perhaps exemplify saying that the delegator only makes a "concession with a reservation of ownership", where the actions never change of owner, can generate more confidence.

This refers to the fact that the actions (SP) will always remain of the "delegator" and that he can recover them at the time he wishes, with only a 7-day waiting margin.