PR是不需要延期的，需要延期的是REP(re-entry permit,就是那个在护照上的章) 。PR does not need to renew, as long as ur re-entry permit is valid, ur PR status will be retained.
to renew REP, the documents needed:
1. A letter (issued not more than one month ago) from the employer addressed to the Controller of Immigration, stating the date of employment, position held and monthly salary;
2. A statement from the CPF Board showing the CPF Contribution History for the last 12 months;
3. Income Tax Notices of Assessment for the last 3 years.
