Ambassador, British Airways; FlyerTalk Posting Legend
Join Date: Apr 2012
Location: Leeds, UK
Programs: BA GGL/CCR, GfL, HH Diamond
Posts: 42,997
For changes you mention the fare restirctions will be the issue on the revenue ticket, not the joker.
I assume you are using the joker to open up reward space in the cabin above for a UuA/GUF? Unless you are paying a large amount for fully flexible fares any change to the ticket is going to incure at least the change fee which is usually several hundred pounds, and also possible repricing of the ticket.