Clandestine Rendezvous pet switching.

Fallen London
1

http://fallenlondon.wikia.com/wiki/A_Clandestine_Rendezvous

I picked the Grubby Kitten from the Urchins.

Now i realize i want a different pet, but i already chose Set your kitten to catching rats in the later option: http://fallenlondon.wikia.com/wiki/What_will_you_do_with_your_Grubby_Kitten%3F

Can i still Swap Pet somehow? Or get another one?

2

You can switch your pet anytime that the specific pet related card turns up.

3

The Grubby Kitten card shows up pretty regularly (I’ve just seen it twice in the last hour). It may take a while if the luck of the draw isn’t on your side, but the chance will come around again