delegate Access for Admin Users

Summary:

we have Delegate option under Actions which is available only for Assignees and not given for Admin users.
Due to this Admin users cannot Delegate approval request incase approvers are on vacation. Reassign cannot be done by our client and Delegate is required for Admin users. Please let us know the solution for this.
why Delegate is not provided with individuals as Admin and owner also (only Assignees given)?

Content (please ensure you mask any confidential information):

Navigation:
BPM Worklist-->ReqApproval-->Access-->Actions-->Delegate

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