How to restrict user to act on behalf of others?

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Hello all,

We would like to know how it is possible to restrict the possibility of a Manager user to act on behalf of other managers. Specifically, we do need our HR users to be able to act on behalf of different managers. Although, when a Manager user needs to use the act as a proxy feature, he or she should be able to act only on behalf of themselves.

How can we achieve this?

Thank you in advance,
Maria

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