Reschedule the return flight? How long I can wait?

Most tickets allow a schedule change depending on the airline, although with the majority of tickets you will have to pay a fee and often a difference in fares (if any). How long you can wait depends on how long the validity is of the ticket you have.

Fares usually go up the closer you get to the date of your return flight, so it may cost more the longer you wait if there is a difference in fares to pay. You also take the chance that the flight you want to change to is sold out, and you can't book the flight no matter how much you pay to do so. In general, it's usually best to try and change sooner rather than later.

In case you can't make a connection due to a delay with the aid of the airline, together with de-planing, the airline will booklet you on the subsequent flight available. However i'd endorse that you leave sufficient time between flights. This won't guarantee that you will not ever omit a connection however it'll support.