Notice to Comply with Lease - Do's and Don'ts

[Alik Levin]

Dear landlords!
Just sent my first Notice to Comply with Lease Agreement after 3 quiet years.

What should be my next step if I come in 14 days to review violations fixed as per the Notice yet the tenants are no show?

Can I enter the premises legally? 

Should I send Notice to vacate?

Else?

Please share your thoughts/experiences?

I am in State of Washington (not DC).

Thank you!

-Alik