You can refinance anytime. The question is appraised value.
Some companies require a seasoning period before they will allow a new appraised value. Most require a 12 month period without proof of serious modifications and upgrades.

You also have to review the terms of your mortgage to make sure you do not have a prepayment penalty. There are ways a lender can get around .

The website below may provide some insight for you.

Good Luck….!

YOU DO NOT HAVE TO HAVE TO MUCH TIME AT ALL THIS PLACE CAN HELP HELP YOU GO TO and they have many lenders to help you

It’s not a matter of time!!! it’s a matter of equity which is the difference between the value of the asset and the amount
owing on it. If your house is worth $200,000, and the mortgage is
$190,000, there is $10,000 in equity in your house (ignoring real estate
commissions, penalties to break mortgages, and other selling costs).
so if there is lots of equity on your house the banks will be more than happy to give you loan or remortgage your house
but now a days i dont think so cause the prices going down and some banks dont trust the houses as an asset unless you have a big downpayment on your house to keep them self in safe side and no risk even the prices going down more
be sure to discuss this with your mortgage broker before you decide to refinance you home

Legally, you are allowed to refinance you house the minute you receive the keys at settlement. In contract terms, it may decide on whether there is a pre-payment penalty written into your financing agreement. Some states have outlawed pre-payment penalties, so even if there is one in there, check with your state’s Attorney General’s office regarding the legality of the pre-payment penalty.

As to rolling debt into the mortgage, you can do that up to the amount of money the new financing bank will provide you. This amount will depend on the balance of your present mortgage compared to the market value of your home. In most cases, you will not be allowed to refinance and take equity out of your house if you go above 90 to 95 percent of the value of your home.

Remember, there are costs involved in refinancing (a new appraisal, closing costs, etc.), so be sure to take them into account when figuring if you can refinance and take money out of the equity.