A bilateral contract can function similar to an option if you have a break clause.It sounds like more reading is in order.

Obligations under a unilateral contract cannot be assigned without consent, bilateral contracts may be assigned unless restricted, a real estate sale contract is a bilateral contract both parties agree to do something.

Unilateral and Bilateral. 

A lease agreement is a bilateral contract between landlord and tenant if the lease says rent is due on the first and late on the third and we do not enforce those late fees on the fourth and start the eviction process as stated in our agreement then technically we are in breach of contract first and not the tenant and we voided the contract before the tenant did.Again maybe that is just in Texas and does not apply in your area or your business model.

It is a legal matter with a bilateral contract, has nothing to do with a due on sale clause.Putting an end buyer or tenant after you buy Sub2 only complicates matters as now you have a contractual obligation to the party in possession.

That's fine, you can get both parties to agree to that and that is another legal option since it is a bi-lateral agreement to end the current lease and re-execute a new lease.

You cannot fake trucks taking out dead bodies to other cities because the morgue doesn’t have space.Northern Italy was a war zone where every room was a covid positive patient where patients were laying on the hallways, where people like you and me were gasping for air and sedated while a nurse or physician in many cases without adequate PPE were holding their hands to their deaths without family members allowed.Each case the same bilateral (meaning both lungs) pneumonia.Truly heartbreaking that we have gotten to this.Please have some respect for the people that died in Italy and if you don’t know what you are talking about limit yourself to talk about real estate.

For instance, owners and tenants should seek written bi-lateral agreements through an attorney when changing terms of a mortgage (or Deed-of-Trust) or lease. 

"Out lot" sales in a commercial shopping center can be 3 or more years out requiring the all kinds of contingencies.Extending purchase agreements happen everyday, while the term of an extension is usually a few days or a month, there is nothing preventing an agreement to be extended for a longer term or as to any right or option to extend a purchase agreement.One and the main difference between the two contracts is that an Option does not (for a true Option) require performance by the optionee or buyer and a purchase contract requires performance by both parties, bi-lateral and uni-lateral agreements.An option may not have any default provision for performance as exercising the option is up to the buyer, the purchase agreement requires performance and carries penalties for non-performance.

You need to know the difference between bilateral agreements and unilateral agreements are and what can be assigned.