When a user navigates to Transactions > Inventory > Reallocate Items is missing even if the user's role has Items permission set to Full.
Add the Sales Order permission to the role and set the permission level to at least Edit. To add this permission:
1. Log in using the Administrator role.
2. Navigate to Setup > Users/Roles > Manage Roles.
3. Edit the role in question.
4. Under Permissions tab > Transactions subtab, add Sales Order.
5. Set Level to at least Edit.
6. Click Save.
Note: If the user still does not see Reallocate Items under Transactions > Inventory after the permission is added, clear cache and try again.