Polite way of requesting extension

[dopey11]

Hello I'd be grateful for some advice on this. My DS is waitlisted for 1st choice indy, with a firm offer on 2nd choice school.

We'll have to negotiate a couple of weeks extension on the deadline of acceptance for the second school - is it best to make up a polite excuse or come clean that we're waiting for a waitlist decision?

IME there isn't room for negotiation. If you accept the second choice you have to pay a deposit and it generally isn't returnable. If you don't pay the deposit you lose the 2nd choice. The 2nd choice has children waiting too.

We just paid up and lost it when we got our first choice a few days later. Pestilence but that's the rules.