If those TONs are locked in your contract you do not have any other option other than having a receiver to withdraw contract's balance. So you need to implement a new operation to withdraw desired amount of TON coins to a specific receptient.

for example:

if (op == op::withdraw()) {
		throw_unless(73, equal_slices(sender_address, admin_address));
		slice to_address = in_msg_body~load_msg_addr();
		int amount = in_msg_body~load_coins();
		
		;; send raw message to "to_address" ...