Like most things, Separation Agreements aren’t necessarily straightforward.
Separation Agreements can only be changed if both parties agree to the changes, as of course any “agreement” requires the parties to be in agreement with one another as to what the contents will be. If you cannot consent or agree to any changes then the Separation Agreement can no longer be relied upon and becomes null.
Furthermore, the Family Court may disregard some or all of its contents if you go on to divorce one another or dissolve your civil partnership.
Ultimately, a Separation Agreement does not represent the final word per se. However, a Separation Agreement entered into upon legal advice and outlining a relatively fair division of any available assets will typically be treated by the Court with respect. Thankfully, Family Courts are now upholding more Separation Agreements than ever before.