What can you do to dilute seasoning when cooking???

An extra teaspoon of thyme shouldn't hurt anything. Your dish (chicken??) might be a little thyme-y but you haven't ruined it. Adding anything else to the crockpot doesn't seem like a good idea as you will most likely dilute all the flavors. A little extra herb can be a good thing! You might like it!

I never measure amounts when I am cooking, and I cook professionally. Everything I cook is to taste. The important thing is to make sure the flavors are balanced. Since you are using a slow cooker, you wont know the effect on the sauce until its almost done cooking. So wait, dont panic, and if before you dish up taste the sauce to see if it needs more seasonings to balance out the little extra thyme you added.

i cook in a kitchen for a resturant i would say add a little more water than usual to dilute it or you can the ever so easy wash it all off and try it again

Potatoes and rice are both great at soaking up salt and seasonings. Add more of one of these should do the trick! (I like to thicken stews with instant mashed potatoes and this helps too!)