If you have an eligible ticket then yes and straight forward (see thread below) assuming availability of course.

More details here.

Same Day Change (SDC) is known as Free Change on the Day (FCOD) within BA. It is available on Plus and CE revenue tickets, single and return, so long as they are not complicated. It is not available on Avios tickets, redemption tickets issued to other frequent flyer schemes, to open jaw tickets, on carriage (tickets with connections) or any other sort of complexity. Also previously changing a ticket with SDC (FCOD) may make it ineligible for SDC, for example if it now becomes open jaw.

https://www.flyertalk.com/forum/brit...ickets-11.html