4 options.

Run the 52t chainring and just buy a bigger cog for the back to get the same gear inches.

Cut the 52t chainring off just above the bolt holes and with a little sanding it might not look too bad.

Go to your lbs and see if they have any used cranks and are willing to trade for something that will allow you to run a 42t chainring.

Sell the cranks on ebay or cl and use the money to buy something that will allow you to run a 42t chainring easier.