Currently an Aha User can only log their own time on a Feature Card.
As a Project Manager / Admin it would be useful to be able to log time on behalf of another User on the project.
All that need be done is add a 'Logged By' Field to the 'Log Time' screen for the Feature. This could be set as a default to the current User, but a drop down list could reveal all the other Users listed against the Product / Product Line.
|Release time frame|
It's currently possible for Product owners (who are not assigned to a feature) to log time on it. From this perspective, you would be able to log time (even if the assignee was out of the office).
Based on your request, it sounds like you might also want to be able to log time for each user. In this latter scenario, we're unlikely to make revisions as we purposely associate features to a single assignee (to ensure that its clear who is responsible for the item). With this in mind, we will mark this as unlikely to implement based on our current priorities, but hope that the initial part can at least help. I hope you can understand.