Visas authorising the applicant to remain in a country have an expiry date. This may be 1 year, 2 years of 5 years from the date of issue of the visa. During that time the person must have a valid residency card.
If you have received an initial visa approval but need to leave the country as a result of some emergency before you have arranged your local residency card you will be unable to return.
Problems can also arise if you need to leave the country in the period when the visa will expire, and you have not yet received your new residency card. Likewise, if your local residency card has been lost or stolen.
Should you find yourself in this situation, it is possible to obtain a ‘Return Authorisation’ from the authorities such that you will be able to take your trip abroad and return, even though you do not have a valid residency card.
Note, for those holding a visa in the European Union do not need a return authorisation to travel to another country in the European Union