Sybase Central lets you update permissions for stored procedures as follows:
Grant and revoke execute permission on a stored procedure.
Grant permission to specific users, groups, or roles, or grant it using the with grant option so the recipient can also grant the permission to other users.
Revoke the permission from specific users, groups, or roles, or revoke it using the with cascade option to revoke it from the named user and all users who acquired permission from the named user, directly or indirectly.
A stored procedure owner can grant and revoke execute permission on the stored procedure.
Updating stored procedure permissions
Select the stored procedure icon, then choose File | Properties.
Click the Permissions tab.
In the Permissions For list, select Users, Groups, or Roles.
To change permissions for an object, click in the Exec column until it indicates the correct permission. The Legend at the bottom of the dialog box explains the symbols.
To see the properties of an object, select it in the list, then click the Properties button.
Click Apply.
Right-click a grid box. Select a permission from the popup menu.