What kind of boot is it?  Attached vulcanized rubber?  Rock boot?  If it's
attached you can have the boot replaced or try to make do by wearing larger
socks or insulating booties.  If they are detached like the Rock Boot, just
buy a different pair.

www.drysuitrepair.com can replace them with different size boots or with
latex or neoprene socks.

I guess it really depends on the manufacturer of the suit,
but the best bet would be to get the right sized boot.
Didn't the shop have you try it on when you bought it?  If
not, THEY need to pay for the boot replacement.  If they did
and you accepted it, then you might be stuck with paying for
the changeover.

Just my $.02

Get bigger feet!   [:])

It's important that you have correctly sized boots properly (professionally)
fitted.

Oversized boots will trap too much air & you may become inverted during a
dive, it may also stop you decoing flat.

I had the boots on both my drysuit and my wife's suit fitted by Hammond
drysuits (www.hammond-drysuits.co.uk) and they did a excellent job (if you
are a UK diver).  They keep many sizes in stock, as they make complete
bespoke drysuiits, however if not in the UK, then find a company where they
will either take your feet measurements or you can visit them & try several
boots until you get ones that fit (taking into account any thermal socks you
would normally wear).

Don't believe the boot makers printed sizes as I've found that they often
are incorrect & vary between different boot makes & styles.

Especially don't get High Heeled or Stiletto boots as it's a bugger trying
to get the fins on and also getting up the boat ladder; not to mention the
comments from other divers (so I won't mention them)!

Based on all the feedback I will have the boots replaced with proper fitting
boots.

Thanks

Frank