For security reasons, since the activities are nominative and therefore personal, only the activity's creator will be able to edit it. For the same reasons, it will not be possible to create an activity on behalf of another person.
The network's administrator will be able to delete the other members' activities, but won't be able to modify them.
We are constantly working on Mobility Work's security measures, therefore we have deemed it appropriate not to allow the creation of activities on behalf of a colleague, nor to modify the activities of others, for legal reasons.