3 Add missing "have"
source | link

In my case when I did my post graduate, I emailed to professor describing why and how I already have the knowledge that is taught in pre-requisite subject (maybe I have already done it somewhere, maybe I have real experience in that field or maybe there is something else that proves I have that knowledge).

And most of the time they were happy to waive it.

But until you apply, you'll have butterflies in your stomach and think that you are only one who is in the class with a waiver, but in most of the cases, after some interactions with other students, you will come to know many students are in with a waiver. So, be confident and just write an email.

In my case when I did my post graduate, I emailed to professor describing why and how I already the knowledge that is taught in pre-requisite subject (maybe I have already done it somewhere, maybe I have real experience in that field or maybe there is something else that proves I have that knowledge).

And most of the time they were happy to waive it.

But until you apply, you'll have butterflies in your stomach and think that you are only one who is in the class with a waiver, but in most of the cases, after some interactions with other students, you will come to know many students are in with a waiver. So, be confident and just write an email.

In my case when I did my post graduate, I emailed to professor describing why and how I already have the knowledge that is taught in pre-requisite subject (maybe I have already done it somewhere, maybe I have real experience in that field or maybe there is something else that proves I have that knowledge).

And most of the time they were happy to waive it.

But until you apply, you'll have butterflies in your stomach and think that you are only one who is in the class with a waiver, but in most of the cases, after some interactions with other students, you will come to know many students are in with a waiver. So, be confident and just write an email.

2 improved grammar
source | link

In my case when I did my post graduate, I I emailed to professor describing why and how I already have thingsthe knowledge that is taught in pre-requisite subject  (may bemaybe I have already done it somewhere, may bemaybe I have real experience in that field or any thingmaybe there is something else that proves youI have that knowledge).

And most of the time they were happy to waive it.

But until you apply you, you'll have butterflybutterflies in your stomach and think that you are only one who is in the class with a waiver, but in most of the cases, after some interactions with other students, you will come to know many students are in with a waiver.So So,be be confident and just write an email.

In my case when I did my post graduate, I emailed to professor describing why and how I already have things that is taught in pre-requisite subject(may be I have already done it somewhere, may be I have real experience in that field or any thing that proves you have that knowledge).

And most of the time they were happy to waive it.

But until you apply you have butterfly in stomach and think that you are only one who is in class with waiver but in most of the cases, after some interactions with other students, you will come to know many students are in with waiver.So,be confident and just write an email.

In my case when I did my post graduate, I emailed to professor describing why and how I already the knowledge that is taught in pre-requisite subject  (maybe I have already done it somewhere, maybe I have real experience in that field or maybe there is something else that proves I have that knowledge).

And most of the time they were happy to waive it.

But until you apply, you'll have butterflies in your stomach and think that you are only one who is in the class with a waiver, but in most of the cases, after some interactions with other students, you will come to know many students are in with a waiver. So, be confident and just write an email.

1
source | link

In my case when I did my post graduate, I emailed to professor describing why and how I already have things that is taught in pre-requisite subject(may be I have already done it somewhere, may be I have real experience in that field or any thing that proves you have that knowledge).

And most of the time they were happy to waive it.

But until you apply you have butterfly in stomach and think that you are only one who is in class with waiver but in most of the cases, after some interactions with other students, you will come to know many students are in with waiver.So,be confident and just write an email.