In business contracts, assignment refers to transferring an agreement's rights, obligations, and property to another party. For example, most commercial tenancy agreements include a clause allowing the tenant to assign their lease to a third party, and that third party becomes the new tenant.
If you communicate clearly, then this is typically not an issue. This is because the seller has signed a legal and binding contract, which makes them obligated to fulfill the terms of the contract. You have every right to perform an assignment of contract when everything has been done legally.