Can this covenant be modified?

When we bought the land we had to sign a covenant restricting the land for certain use. For example, you can’t put a single wide mobile home on the land,etc.

There is also a paragraph that states that the only residence permitted on the land will be one single family dwelling.

We have some people very interested in the land, and are willing to put $18,000 down. However, they want to build two houses.

I emailed my attorney (who I saw today to draw up the contract,) but haven’t heard back.

Do any of you know if this can be modified? It’s in effect until December of 2023.