Changing one's intention from building a mosque to other charitable channels
I purchased a plot of residential land in 10th of Ramadan city some years ago. When I felt that I no longer needed it, or will not build on it because I left the country, I contacted the city council through an agent and informed them that I wished to construct a mosque on it. They replied that this was not possible as the land is located in a residential area but recommended that I sell it and use the money to construct a mosque or participate in the building of one in the area allotted for mosques. I agreed and sold the plot of land. But when I returned, I discovered that there are many avenues for charity that are more important than building mosques, such as participating in establishing endowments for Islamic intellectual works, supporting orphans, financing social projects in my village and others of which I was previously unaware.
My question is: Is it permissible to change my intention from constructing a mosque
Yes, it is permissible provided you did not make a vow to use this sum towards building a mosque. You are free to spend your money on anything that, in your opinion, best serves the interest of Muslims and you are not blameworthy.
Allah Almighty knows best.