Originally Posted by
Bukhara
B and H have always been non-changeable on day of departure.
I always hate to try and contradict you,
Bukhara 
But I was also under the impression they were changeable subject to upgrading to a higher fare (in fact I mentioned it on the other thread today too coincidentally) at any time. I dug out an old rule PDF I had saved from March 2006 when BA used to (
) publish them:
Code:
5374 B & H CLASS FARES.
Application Economy class OW/RT/OJ. Fares only apply if purchased
before departure
Flight application BA only. For NDOMNBA on EDI-LON not permitted on
BA4201-8. For GLA-SDZ only on BA8775/6/7. IOM-LON only on BA4331-
6. PLH-ABZ only on direct or flights via NCL/BRS/LGW. For PLH-GLA/NCL
only on direct or via BRS/LGW/NQY No interlining.
Reservations/Payment/Ticketing All sectors must be booked at same
time. Ticketing must be completed within 72 hours.
Cancellation No refund.
(Note A as shown in rule 5372 applies)
Stopovers Not permitted.
Transfers: Not permitted except that between PLH and ABZ/GLA/NCL
travel can be via BRS/LGW/NQY.
Cancellations No refund
Changes Not permitted except to upgrade to a J/C/Y class fare upon
payment of difference in fare. The original cancellation penalty will apply if
the upgraded ticket is subsequently cancelled.
Combinations Fares may be combined on a half round trip basis to form
round trips/Single open jaws with fares covered by any BA rules
End-on-End combinations permitted with domestic fares. Constructions
with add-ons not permitted.
Children No discount. Infants Pay 10%.
Agents/Tour Conductors discount Not permitted.
That applied (for example) a bog standard LON-EDI HDOMCBA 189.00 fare. For a HEUCBA (e.g. LON-AMS) it was:
Code:
5589 ECONOMY UGRADEABLE (SEMI FLEXIBLE)FARE.
Application Economy class RT/OJ. Fares only apply if purchased before
departure
Flight application BA only. No interlining except with BD between BFS
and Europe/LO within Poland/IB on Europe
Reservations/Payment/Ticketing All sectors must be booked at same
time. Ticketing must be completed within 72 hours. Conditions of Sale
sticker: required
Min/Max stay No min/Max one year
Stopovers Not permitted.
Transfers Permitted within routing.
Combinations Fares may be combined on a half round trip basis to form
round trips/Single and Double open jaws with fares covered by rules
5582/5584-90/5592-94/5596/5617-19 and 8368-76/8388-90(Fare rules
for each sector apply).
End-on-End combinations: permitted within Europe. Construction with
Add-Ons: Permitted in UK
Cancellation No refund. (Note A: shown in Rule 5576 applies)
Changes Not permitted except to upgrade to a J/C/Y class fare.
Children No discount. Infants Pay 10%.
Agents/Tour Conductors discount Not permitted.
Am I misreading them? Nothing about 'except on day of departure' - or does it not being listed not mean that it didn't apply. If you follow!