How to reply to another Guild Member?

13/06/17 15:03
How do I reply to someone in another Guild? I sent him an invite to ours and he sent me a nice reply, politely declining so I would like to reciprocate but do not know how.

[EDIT] Maybe they will see this. The team in question is "Burntisland Buccaneers" of the Guild "Edinburgh Rugby". Thanks for the game, only being online and being able to use my subs won me the game. Also thanks for the nice reply but I am the same, this is a feeder Guild for our other one so I am happy where I am. Thanks for the invite also