You can create a lane that exists only in the referential tariff and does not appear on the corresponding master tariff.
If the master tariff contains lanes that are not wanted on the referential tariff, you can creating a lane for the referential tariff that is identical to the unneeded lane on the master tariff, with the exception that the Lane Status is Blocked.
To override a lane in the master tariff, you can create a lane in the referential tariff that is identical to the one you want to override, then give this lane a new rate code. Once a lane is defined for the referential tariff, it is considered an override to the master tariff, and will be applied even if the rate in the master tariff is less expensive.