Help Needed Rental adjustment for change in underlying interest rate, fixed IRR Target

Hello Everyone,

First time post here!

I have been trying to come up with an excel formula for the following problem. Assume I am purchasing a deprecating asset, with leverage, to lease and eventually sell. I use the cost of debt as of today to get my IRR, lets say that the interest rate is for the debt is 6%. Based on this, I agree to buy the asset for 23m, collect 60 monthly rent payments of 230k, and sell my asset at the end of the period for 18m. My IRR is 15%. Now I assume some time has passed from my original analysis and the cost of my debt is now 7%, leaving all other inputs unchanged my IRR is now 12.6% but I want it to be 15% and the only option is to change the rent.

I can solve this with goal seek but it would be very useful to have a formula work this out, can anyone help me out?

Thanks