There should be a configuration parameter for store user to suspend transaction when partial payment is done.

Business scenario

Customer is using table management feature, Where 1st Guest comes and store user select Table 1 and proceed with adding items to transaction cart. Here Total amount is 100 USD and 1st guest will pay 50 USD.(Here transaction number is 001) Store user should be able to suspend transaction.

Now 2nd Guest joins the Table 1 after some time, now store user should be able to resume the above transaction. Store user should be able proceed with adding new items to transaction cart and should be able to do the full payment and complete transaction on POS.