diff --git a/src/controllers/PermissionController.ts b/src/controllers/PermissionController.ts
index e056f01..5304fee 100644
--- a/src/controllers/PermissionController.ts
+++ b/src/controllers/PermissionController.ts
@@ -1,12 +1,14 @@
-import { Body, Delete, Get, JsonController, OnUndefined, Param, Post, QueryParam } from 'routing-controllers';
+import { Body, Delete, Get, JsonController, OnUndefined, Param, Post, Put, QueryParam } from 'routing-controllers';
 import { OpenAPI, ResponseSchema } from 'routing-controllers-openapi';
 import { getConnectionManager, Repository } from 'typeorm';
-import { PermissionNotFoundError } from '../errors/PermissionErrors';
-import { PrincipalNotFoundError } from '../errors/PrincipalsErrors';
+import { PermissionIdsNotMatchingError, PermissionNeedsPrincipalError, PermissionNotFoundError } from '../errors/PermissionErrors';
+import { PrincipalNotFoundError } from '../errors/PrincipalErrors';
 import { CreatePermission } from '../models/actions/CreatePermission';
+import { UpdatePermission } from '../models/actions/UpdatePermission';
 import { Permission } from '../models/entities/Permission';
 import { ResponseEmpty } from '../models/responses/ResponseEmpty';
 import { ResponsePermission } from '../models/responses/ResponsePermission';
+import { ResponsePrincipal } from '../models/responses/ResponsePrincipal';
 
 
 @JsonController('/permissions')
@@ -64,13 +66,15 @@ export class PermissionController {
         return new ResponsePermission(permission);
     }
 
-    /*
+
     @Put('/:id')
     @ResponseSchema(ResponsePrincipal)
     @ResponseSchema(PermissionNotFoundError, { statusCode: 404 })
+    @ResponseSchema(PrincipalNotFoundError, { statusCode: 404 })
     @ResponseSchema(PermissionIdsNotMatchingError, { statusCode: 406 })
-    @OpenAPI({ description: "Update a runnerTeam object (id can't be changed)." })
-    async put(@Param('id') id: number, @EntityFromBody() permission: Permission) {
+    @ResponseSchema(PermissionNeedsPrincipalError, { statusCode: 406 })
+    @OpenAPI({ description: "Update a permission object (id can't be changed)." })
+    async put(@Param('id') id: number, @Body({ validate: true }) permission: UpdatePermission) {
         let oldPermission = await this.permissionRepository.findOne({ id: id }, { relations: ['principal'] });
 
         if (!oldPermission) {
@@ -81,10 +85,10 @@ export class PermissionController {
             throw new PermissionIdsNotMatchingError();
         }
 
-        await this.permissionRepository.update(oldPermission, permission);
+        await this.permissionRepository.update(oldPermission, await permission.toPermission());
 
         return new ResponsePermission(await this.permissionRepository.findOne({ id: permission.id }, { relations: ['principal'] }));
-    }*/
+    }
 
     @Delete('/:id')
     @ResponseSchema(ResponsePermission)
diff --git a/src/errors/PermissionErrors.ts b/src/errors/PermissionErrors.ts
index e53b143..c2492b4 100644
--- a/src/errors/PermissionErrors.ts
+++ b/src/errors/PermissionErrors.ts
@@ -22,4 +22,15 @@ export class PermissionIdsNotMatchingError extends NotAcceptableError {
 
 	@IsString()
 	message = "The id's don't match!! \n And if you wanted to change a permission's id: This isn't allowed"
+}
+
+/**
+ * Error to throw when a permission get's provided without a principal.
+ */
+export class PermissionNeedsPrincipalError extends NotAcceptableError {
+	@IsString()
+	name = "PermissionNeedsPrincipalError"
+
+	@IsString()
+	message = "You provided no principal for this permission."
 }
\ No newline at end of file
diff --git a/src/errors/PrincipalErrors.ts b/src/errors/PrincipalErrors.ts
new file mode 100644
index 0000000..d519dc7
--- /dev/null
+++ b/src/errors/PrincipalErrors.ts
@@ -0,0 +1,24 @@
+import { IsString } from 'class-validator';
+import { NotAcceptableError, NotFoundError } from 'routing-controllers';
+
+/**
+ * Error to throw when a user couldn't be found.
+ */
+export class PrincipalNotFoundError extends NotFoundError {
+	@IsString()
+	name = "PrincipalNotFoundError"
+
+	@IsString()
+	message = "Principal not found!"
+}
+
+/**
+ * Error to throw, when a provided runnerOrganisation doesn't belong to the accepted types.
+ */
+export class PrincipalWrongTypeError extends NotAcceptableError {
+	@IsString()
+	name = "PrincipalWrongTypeError"
+
+	@IsString()
+	message = "The princial must have an existing principal's id. \n You provided a object of another type."
+}
diff --git a/src/errors/PrincipalsErrors.ts b/src/errors/PrincipalsErrors.ts
deleted file mode 100644
index 73e9819..0000000
--- a/src/errors/PrincipalsErrors.ts
+++ /dev/null
@@ -1,13 +0,0 @@
-import { IsString } from 'class-validator';
-import { NotFoundError } from 'routing-controllers';
-
-/**
- * Error to throw when a user couldn't be found.
- */
-export class PrincipalNotFoundError extends NotFoundError {
-	@IsString()
-	name = "PrincipalNotFoundError"
-
-	@IsString()
-	message = "Principal not found!"
-}
\ No newline at end of file
diff --git a/src/models/actions/CreatePermission.ts b/src/models/actions/CreatePermission.ts
index 829bff1..d7fe91a 100644
--- a/src/models/actions/CreatePermission.ts
+++ b/src/models/actions/CreatePermission.ts
@@ -3,7 +3,7 @@ import {
     IsNotEmpty
 } from "class-validator";
 import { getConnectionManager } from 'typeorm';
-import { PrincipalNotFoundError } from '../../errors/PrincipalsErrors';
+import { PrincipalNotFoundError } from '../../errors/PrincipalErrors';
 import { Permission } from '../entities/Permission';
 import { Principal } from '../entities/Principal';
 import { PermissionAction } from '../enums/PermissionAction';
diff --git a/src/models/actions/UpdatePermission.ts b/src/models/actions/UpdatePermission.ts
new file mode 100644
index 0000000..26c2a83
--- /dev/null
+++ b/src/models/actions/UpdatePermission.ts
@@ -0,0 +1,65 @@
+import { IsInt, IsNotEmpty, IsObject } from 'class-validator';
+import { getConnectionManager } from 'typeorm';
+import { PermissionNeedsPrincipalError } from '../../errors/PermissionErrors';
+import { PrincipalNotFoundError, PrincipalWrongTypeError } from '../../errors/PrincipalErrors';
+import { Permission } from '../entities/Permission';
+import { Principal } from '../entities/Principal';
+import { PermissionAction } from '../enums/PermissionAction';
+import { PermissionTarget } from '../enums/PermissionTargets';
+
+export class UpdatePermission {
+
+    /**
+     * The updated runner's id.
+     */
+    @IsInt()
+    id: number;
+
+    /**
+     * The permissions's principal's id.
+     */
+    @IsObject()
+    @IsNotEmpty()
+    principal: Principal;
+
+    /**
+     * The permissions's target.
+     */
+    @IsNotEmpty()
+    target: PermissionTarget;
+
+    /**
+     * The permissions's action.
+     */
+    @IsNotEmpty()
+    action: PermissionAction;
+
+    /**
+     * Converts a Permission object based on this.
+     */
+    public async toPermission(): Promise<Permission> {
+        let newPermission: Permission = new Permission();
+
+        newPermission.principal = await this.getPrincipal();
+        newPermission.target = this.target;
+        newPermission.action = this.action;
+
+        return newPermission;
+    }
+
+    /**
+     * Manages all the different ways a group can be provided.
+     */
+    public async getPrincipal(): Promise<Principal> {
+        if (this.principal === undefined) {
+            throw new PermissionNeedsPrincipalError();
+        }
+        if (!isNaN(this.principal.id)) {
+            let principal = await getConnectionManager().get().getRepository(Principal).findOne({ id: this.principal.id });
+            if (!principal) { throw new PrincipalNotFoundError(); }
+            return principal;
+        }
+
+        throw new PrincipalWrongTypeError();
+    }
+}
\ No newline at end of file