Hi gent2,
1st u ave 2 wait 4 them 2 request for ur passport,and even when they do,there is no need 4 u 2 write a letter etc.yes,u can get a new passport B4 ppr infact,its better u do.also when immig issues a new passport,u r xpected 2 cancel d old one as u r not xpected 2 b carrying 2 valid...