post
https://api.qfp.quantnetwork.net/api/approvals/tasks//reassign
approverExpr keeps the expression the task was created with, while
approverIds is replaced by what the target resolves to: a group's
members, or the one user id named directly. The move is recorded on
the task as reassignedFrom, reassignedBy, reassignedAt and
reassignReason.
The request and the task must both be PENDING (409). The resolved
set is pruned of the request's initiatedBy (four-eyes) and must not
end up empty (400) or equal to the current set (409); any member of
it may then decide. Any authenticated caller in the tenant may
reassign.