If you want to call a variation there would be a charge deducted from the IVA pot. There should be nothing extra to pay and the actual variation fee is normally in the region of £300-£500.
Firstly if your circumstances have changed since entering into the IVA then you should advise your IP as repayments are based on your income and expenditure and if this no longer accurate then it is likely that the repayments are not either.
Secondly if you are fortunate enough to have a family member who is able to offer you a lump sum, you should contact your IP and advise them that you would like them to hold a variation meeting with your creditors for a full and final settlement for £20k.
Although this amount is less then what you would have paid in total over the term of the IVA the creditors should take into account that they will receive this payment a lot quicker.
Bridgewood specialise in helping people deal with their debts and make the most of their financial situation - providing free, no obligation debt advice.
We can also setup a complete range of solutions including debt management plans, IVA and bankruptcy support.