#include<bits/stdc++.h>//0xnnb
using namespace std;
typedef long long ll;
typedef double db;
int read(){
    int x=0,f=1;
    char ch=getchar();
    while(ch<'0'||ch>'9'){
        if(ch=='-')f=-1;
        ch=getchar();
    }
    while(ch>='0'&&ch<='9'){
        x=x*10+ch-'0';
        ch=getchar();
    }
    return x*f;
}
const int N=105;
int T,n,m,a[N][N];
char s[N];
bool flag;
void dfs(int x,int y);
void check(int x,int y){
	if(x<1||x>=n||y<1||y>=m)return;
	if(a[x][y]<=1&&a[x][y+1]<=1&&a[x+1][y]<=1&&a[x+1][y+1]<=1)return;
	if(a[x][y+1]<=1&&a[x+1][y]<=1&&a[x+1][y+1]<=1){
		if(a[x][y+1]==a[x+1][y]&&a[x][y+1]==a[x+1][y+1]){
			a[x][y]=a[x][y+1]^1;
			dfs(x,y);
		}
	}
	else if(a[x][y]<=1&&a[x+1][y]<=1&&a[x+1][y+1]<=1){
		if(a[x][y]==a[x+1][y]&&a[x][y]==a[x+1][y+1]){
			a[x][y+1]=a[x][y]^1;
			dfs(x,y+1);
		}
	}
	else if(a[x][y]<=1&&a[x][y+1]<=1&&a[x+1][y+1]<=1){
		if(a[x][y]==a[x][y+1]&&a[x][y]==a[x+1][y+1]){
			a[x+1][y]=a[x][y]^1;
			dfs(x+1,y);
		}
	}
	else if(a[x][y]<=1&&a[x][y+1]<=1&&a[x+1][y]<=1){
		if(a[x][y]==a[x][y+1]&&a[x][y]==a[x+1][y]){
			a[x+1][y+1]=a[x][y]^1;
			dfs(x+1,y+1);
		}
	}
}
void dfs(int x,int y){
	check(x-1,y-1);
	check(x-1,y);
	check(x,y-1);
	check(x,y);
}
int main(){
	srand(time(NULL));
	T=read();
	while(T--){
		n=read(),m=read();
		for(int i=1;i<=n;i++){
			scanf("%s",s+1);
			for(int j=1;j<=m;j++){
				if(s[j]=='B')a[i][j]=1;
				else if(s[j]=='W')a[i][j]=0;
				else a[i][j]=2;
			}
		}
		for(int i=1;i<=n;i++){
			for(int j=1;j<=m;j++){
				if(((i+j)&1)&&a[i][j]<=1){
					a[i][j]^=1;
				}
			}
		}
		flag=1;
		for(int i=1;i<n;i++){
			for(int j=1;j<m;j++){
				if(a[i][j]<=1&&a[i][j+1]<=1&&a[i+1][j]<=1&&a[i+1][j+1]<=1){
					if(a[i][j]==a[i][j+1]&&a[i][j]==a[i+1][j]&&a[i][j]==a[i+1][j+1]){
						flag=0;
						break;
					}
				}
				check(i,j);
			}
			if(!flag)break;
		}
		if(!flag){
			printf("NO\n");
			continue;
		}
		for(int i=1;i<=n;i++){
			for(int j=1;j<=m;j++){
				if(a[i][j]!=2)continue;
				a[i][j]=rand()&1;
				dfs(i,j);
			}
		}
		printf("YES\n");
		for(int i=1;i<=n;i++){
			for(int j=1;j<=m;j++){
				if((i+j)&1){
					a[i][j]^=1;
				}
				if(a[i][j])putchar('B');
				else putchar('W');
			}
			printf("\n");
		}
	}
    return 0;
}