Can a ex Manager be pursued to conduct Performance appraisal of its ex team members?

Zee_A
To the concerned HR experts,
I am just confronted with this rare query and my organizational policy do not have any explicit provisions about it. One of our department heads resigned about three months ago, and a new replacement has joined some 2 months ago. We need to conduct annual performance appraisals of a department team, however it is obvious that the existing department head (who joined 2 months ago) cannot do it alone since he wasn't with team most part of the year, therefore can he formally take feedback or involve the ex-department head, since the team worked most part of the year under him, in the appraisal?
To summarize it, can a organization approach an ex employee to seek his/her feedback or involve them in the performance evaluation of their ex reporting staff?
Thank you in advance for your kind support.
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