You can change manually the contact owner at any time.
As a manager you can operate on all contacts, and as a user only on contacts you already own.
To change the contact owner:
1. Go to the Contact view and select the contact(s)
2. Click on Actions and then on Change ownership
3. A window appears:
4. Select the name of the user (with the picklist) who will become the new owner and click on Submit.
By default, the contact owner is the user who created it or the last user who added it to a sequence.
Another option to change the contact owner:
You can go directly to the contact's profile and in the text area on the far right you click on Owner in the Info tab. Then click in the text area to see the different users of your company. Choose the one you want to be the owner of the contact then click on Save (Be careful it will not be possible to change the contact owner through this option if the contact is active in a sequence, the field will be greyed out).