#include<bits/stdc++.h>
using namespace std;
const int N=105,M=10005;
int T;
int n,m;
char a[N][N];
int typ[N][N];
struct nd
{
	int x,y;
	bool operator <(const nd &b) const
	{
		return x<b.x||x==b.x&&y<b.y;
	}
};
set <nd> hav1,hav2;
set <nd> ::iterator it;
bool upd(int x,int y)
{
	if(x<1||y<1||x>=n||y>=m) return true;
	if(1<=typ[x][y]&&typ[x][y]<=2)
	{
		if(typ[x][y]==1) hav1.erase((nd){x,y});
		if(typ[x][y]==2) hav2.erase((nd){x,y});
	}
	int cnt=(a[x][y]=='?')+(a[x+1][y]=='?')+(a[x][y+1]=='?')+(a[x+1][y+1]=='?');
	if(cnt==0&&a[x][y]=='W'&&a[x+1][y+1]=='W'&&a[x+1][y]=='B'&&a[x][y+1]=='B') return false;
	if(cnt==0&&a[x][y]=='B'&&a[x+1][y+1]=='B'&&a[x+1][y]=='W'&&a[x][y+1]=='W') return false;
	if((a[x][y]==a[x+1][y]||a[x][y]==a[x+1][y+1])&&a[x][y]!='?') cnt=0;
	if((a[x+1][y]==a[x+1][y+1]||a[x][y+1]==a[x+1][y+1])&&a[x+1][y+1]!='?') cnt=0;
	if(a[x][y]!=a[x+1][y+1]&&a[x][y]!='?') cnt=0;
	if(a[x+1][y]!=a[x][y+1]&&a[x+1][y]!='?') cnt=0;
	if(cnt==2)
	{
		if(a[x][y]=='?'&&a[x+1][y]=='?') cnt=0;
		if(a[x][y]=='?'&&a[x][y+1]=='?') cnt=0;
		if(a[x][y+1]=='?'&&a[x+1][y+1]=='?') cnt=0;
		if(a[x+1][y]=='?'&&a[x+1][y+1]=='?') cnt=0;
	}
	typ[x][y]=cnt;
	if(1<=typ[x][y]&&typ[x][y]<=2)
	{
		if(typ[x][y]==1) hav1.insert((nd){x,y});
		if(typ[x][y]==2) hav2.insert((nd){x,y});
	}
	return true;
}
bool update(int x,int y)
{
	if(!upd(x-1,y-1)) return false;
	if(!upd(x,y-1)) return false;
	if(!upd(x-1,y)) return false;
	if(!upd(x,y)) return false;
	return true;
}
bool check()
{
	for(int i=1;i<n;i++)
		for(int j=1;j<m;j++)
			if(!upd(i,j)) return false;
	while(!hav1.empty()||!hav2.empty())
	{
		if(!hav1.empty())
		{
			it=hav1.begin();
			int x=(*it).x,y=(*it).y;hav1.erase(it);
//			printf("1:%d %d\n",x,y);
			int tmpx=0,tmpy=0;
			if(a[x][y]=='?') tmpx=x,tmpy=y,a[tmpx][tmpy]=a[x][y+1];
			if(a[x+1][y]=='?') tmpx=x+1,tmpy=y,a[tmpx][tmpy]=a[x][y];
			if(a[x][y+1]=='?') tmpx=x,tmpy=y+1,a[tmpx][tmpy]=a[x][y];
			if(a[x+1][y+1]=='?') tmpx=x+1,tmpy=y+1,a[tmpx][tmpy]=a[x][y+1];
			if(!update(tmpx,tmpy)) return false;
			continue;
		}
		if(!hav2.empty())
		{
			it=hav2.begin();
			int x=(*it).x,y=(*it).y;hav2.erase(it);
			int tmpx=0,tmpy=0;
			if(a[x][y]=='?') tmpx=x,tmpy=y,a[x][y]=a[x+1][y];
			if(a[x+1][y]=='?') tmpx=x+1,tmpy=y,a[x+1][y]=a[x][y];
			if(!update(tmpx,tmpy)) return false;
			continue;
		}
	}
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++) if(a[i][j]=='?') a[i][j]='W';
	return true;
}
void init()
{
	hav1.clear();
	hav2.clear();
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++) typ[n][m]=0;
}
int main()
{
	scanf("%d",&T);
	while(T--)
	{
		scanf("%d%d",&n,&m);
		for(int i=1;i<=n;i++)
			for(int j=1;j<=m;j++) scanf(" %c",&a[i][j]);
		if(!check()){printf("NO\n");continue;}
		printf("YES\n");
		for(int i=1;i<=n;i++){
			for(int j=1;j<=m;j++) printf("%c",a[i][j]);printf("\n");}
	}
}