How to raise rent when in lease

[Ali BenAyed]

I offered a 4 year lease which has 2 years left and now I’m trying to get out of it with the least of problems. The tenant is excellent, they pay on time and keep the house in a good condition, except that I suspect they recently added a 2nd dog when the lease agreement has only 1 dog. The current lease is $1330/month including the 1 dog rent and similar units are getting rented for up to $1600/month for a more renovated unit and a pet rent of $50/month per pet. The lease agreement has a mistake in its phrasing that could be void the contract. Although I still need to consult with an expert in contract laws but the contract can be voided for having 2 contradicting phrases. And I don’t have prove the tenant has 2 dogs, but I can have witnesses who saw them and social media stories. I’m not sure how to proceed. Any ideas how to be able to increase rent?