what does this mean?
We reserve the right to withdraw this offer if not accepted and a mutually agreeable contract fully executed by that date.

i don't understand this part: "and a mutually agreeable contract fully executed by that date" does it mean" and a mutually agreeable contract NOT fully executed by that date"??

Question

what does this mean?
We reserve the right to withdraw this offer if not accepted and a mutually agreeable contract fully executed by that date.

i don't understand this part: "and a mutually agreeable contract fully executed by that date"  does it mean" and a mutually agreeable contract NOT fully executed by that date"??

Answer

The "and" is wrong!

We reserve the right to withdraw this offer if not accepted OR (if) a mutually agreeable contract (is not) fully executed by that date.

Now it all makes sense.

Answer

I think it means something like "We reserve the right to withdraw this offer if not accepted and [we reserve the right to] a mutually agreeable contract fully executed by that date." 
We sometimes drop words in English, so some sentences can be difficult to understand.

Answer

Everybody missed the incorrect AND.

Answer

both parties have to come to the same agreement by a specific date/deadline.

Answer

But most people reserve the right to "cancel" a contract. Why here they reserve the right to a mutually agreeable contract? If mutually agreeable then just sign it, why reserve the right?