MoEngage Docs

Updating User Attribute Unique Id

If for some reason the app needs to update the user attribute unique id use the method setAlias() instead of again calling setUniqueId() with a different value.
Calling setUniqueId() with a new value will lead to creation of unintended users in our system.

MoEHelper.getInstance(getContext()).setAlias();

Minimum SDK Version: 8.0.05